Environment and Health

What to remember

• A polluted or disturbed environment causes disease through air, water, food, soil and vectors. Climate change adds heat stress and spreads vector-borne disease.
• Vector-borne diseases are spread by insects (mosquito, sandfly, mite). Water-borne diseases are spread by contaminated water. Know the vector or germ for each disease.
• Safe water, sanitation and clean cooking fuel are the strongest public-health tools. Schemes such as Swachh Bharat, Jal Jeevan Mission and Ujjwala target these.

How environment affects health

Health depends on clean air, safe water, safe food, sanitation, a safe home and a stable climate. Poor environment brings respiratory disease, diarrhoea, poisoning, cancers and infections. The poor suffer most because they live closest to pollution and have the least access to services. Good environment management is therefore also preventive medicine.

Vector-borne diseases

A vector is a living carrier that transmits an infectious agent from one host to another. Control focuses on killing vectors, removing breeding sites, using nets and repellents, and treating patients.

Malaria uses the Anopheles mosquito for its sexual stage, and the human is the host for the asexual stage. Larvae-eating fish such as Gambusia are used in biological control.

Water-borne diseases

Contamination by sewage is the usual cause. Faecal-oral spread links poor sanitation to disease.

Oral rehydration solution (ORS) saves lives in diarrhoea. Prevention includes boiling, chlorination, filtering, handwashing and proper toilets.

Chemical contamination of water also harms health:

• Fluorosis from excess fluoride in groundwater, which damages teeth and bones. Some parts of AP are fluoride-affected.
• Arsenicosis from arsenic in groundwater (well known in the Ganga delta region).
• Methaemoglobinemia (blue baby syndrome) from high nitrate in water.
• Lead and mercury poisoning. Minamata disease came from mercury, and itai-itai disease from cadmium.
• A kidney disease of unknown cause has been reported in the Uddanam coastal area of north coastal AP.

Air pollution and health

Main pollutants are particulate matter (PM10 and the finer PM2.5), sulphur dioxide, nitrogen oxides, carbon monoxide, ozone, lead and volatile organic compounds. Fine particles penetrate deep into the lungs and even the blood.

Indoor air pollution from burning wood, dung or coal on traditional stoves badly affects women and children. The Pradhan Mantri Ujjwala Yojana gives LPG connections to poor households to reduce this. The Air Quality Index (AQI) converts pollutant values into six categories: Good, Satisfactory, Moderate, Poor, Very Poor and Severe. The National Clean Air Programme (NCAP) sets city-level plans to cut particulate pollution. The Bhopal gas tragedy (methyl isocyanate leak) is the worst industrial gas disaster in India.

Transgenic crops and biosafety

A transgenic (genetically modified) organism carries a gene from another species. Bt cotton contains a Cry gene from the soil bacterium *Bacillus thuringiensis*, which produces a protein toxic to bollworm. It is the only GM crop approved for commercial farming in India, since the early 2000s. Bt brinjal got a moratorium, after objections, and has not been released.

Biosafety means safeguards against risks of GMOs to health and the environment: allergies, gene flow to wild relatives, harm to non-target insects, resistance in pests, and loss of biodiversity.

Climate and health

Climate change affects health through heat stress and heat stroke, more intense floods and cyclones, spread of dengue and malaria to new areas and seasons, water-borne outbreaks after floods, crop failure and malnutrition, and mental stress from displacement. Cities add a heat island effect. Responses include heat action plans, disease surveillance, climate-resilient health facilities and nutrition programmes.

Sanitation

Poor sanitation means open defecation, untreated sewage and poor solid waste handling. It causes diarrhoea, worm infections and stunting in children. The Swachh Bharat Mission (launched 2014) promoted toilet construction and ending open defecation, with later phases focusing on waste management and sustaining use. Septic tanks, sewage treatment plants and faecal sludge management are the main technologies. The AMRUT mission supports water supply and sewerage in towns.

Safe drinking water programmes

Safe water is free of germs, harmful chemicals and bad taste or smell. India uses Bureau of Indian Standards specifications for drinking water.

The Jal Jeevan Mission (launched 2019) aims to give every rural household a functional tap water connection. It replaced and built upon the earlier National Rural Drinking Water Programme. Water quality testing, community management of supply and protection of sources are key parts. Groundwater protection and watershed work also help.

Other environment-linked health problems

• Noise pollution causes stress, hearing loss, sleep loss and high blood pressure. It is measured in decibels.
• Pesticide exposure can harm the nervous system, and residues in food and water raise cancer and birth-defect concerns. Integrated pest management cuts pesticide use.
• Heavy metals such as lead, mercury and cadmium collect in the food chain (biomagnification) and cause lasting damage.
• Radiation from nuclear accidents or excessive exposure can cause cancer. Ultraviolet rays rise when the ozone layer thins, increasing skin cancer and cataract.
• Solid and e-waste that is burned or dumped releases toxic fumes and leaches harmful chemicals into soil and water.
• Food safety is affected by contaminated water, adulteration and unhygienic handling, and leads to food-borne illness.

Prevention approach

Public health uses three levels. Primary prevention stops disease before it starts, through clean water, sanitation, vaccination, nets and clean fuel. Secondary prevention finds disease early, through screening and surveillance. Tertiary prevention treats and rehabilitates. The "One Health" idea links human, animal and environmental health, because many diseases pass between animals and people.

Disease control programmes and surveillance

India runs national programmes for vector-borne diseases, which use surveillance, fogging and larvicide, insecticide-treated nets, rapid tests and free treatment. Elimination goals exist for malaria, filariasis and kala-azar. Health workers such as ASHAs help by spreading awareness and getting patients to treatment. Integrated vector management combines environmental steps (draining stagnant water, covering tanks), biological steps (larvae-eating fish) and chemical steps (insecticide), and works better than any single method. After floods and cyclones, health teams chlorinate wells and watch for outbreaks of diarrhoea, cholera and leptospirosis. Leptospirosis spreads through water contaminated by the urine of rats and other animals.

Exam traps

• Anopheles vs Aedes vs Culex: malaria, dengue/chikungunya, and filariasis/Japanese encephalitis respectively.
• Aedes bites by day; Anopheles bites at night.
• Vector-borne vs water-borne: cholera, typhoid and hepatitis A are water-borne, not mosquito-borne.
• Fluorosis vs arsenicosis: fluoride affects teeth and bones. Arsenic affects skin and organs.
• Blue baby syndrome: nitrate, not fluoride.
• Bt cotton: the only GM crop approved for commercial cultivation, not Bt brinjal.
• GEAC vs NGT: GEAC clears GMOs; NGT hears environmental cases.
• Cartagena Protocol: biosafety, not climate. Do not confuse it with Kyoto or Nagoya.

One-liners

• 1. Female Anopheles transmits malaria.
• 2. Aedes aegypti transmits dengue.
• 3. Culex transmits filariasis and Japanese encephalitis.
• 4. Sandfly transmits kala-azar.
• 5. Cholera is caused by Vibrio cholerae.
• 6. Typhoid is caused by Salmonella Typhi.
• 7. Carbon monoxide reduces the blood's oxygen-carrying capacity.
• 8. Minamata disease came from mercury.
• 9. Bt cotton is India's only commercially approved GM crop.
• 10. GEAC approves GMO releases.
• 11. The Cartagena Protocol deals with biosafety.
• 12. Jal Jeevan Mission targets tap water for rural households.

Practice questions

1. Malaria is spread by the female

   1. Tsetse fly
   2. Anopheles mosquito
   3. Culex mosquito
   4. Aedes mosquito
   Answer

   B. Anopheles mosquito

   Female Anopheles carries Plasmodium.

2. Dengue is transmitted by

   1. Sandfly
   2. Anopheles
   3. Culex
   4. Aedes aegypti
   Answer

   D. Aedes aegypti

   Aedes aegypti, which bites by day, spreads dengue.

3. Filariasis is spread by

   1. Aedes mosquito
   2. Culex mosquito
   3. Housefly
   4. Sandfly
   Answer

   B. Culex mosquito

   Culex carries the filarial worm.

4. Kala-azar is spread by the

   1. Mosquito
   2. Sandfly
   3. Tick
   4. Louse
   Answer

   B. Sandfly

   The sandfly carries Leishmania donovani.

5. The cause of cholera is

   1. Shigella
   2. Salmonella Typhi
   3. Plasmodium
   4. Vibrio cholerae
   Answer

   D. Vibrio cholerae

   Cholera is a bacterial disease from Vibrio cholerae.

6. Typhoid is caused by

   1. Vibrio cholerae
   2. Entamoeba histolytica
   3. Poliovirus
   4. Salmonella Typhi
   Answer

   D. Salmonella Typhi

   Typhoid is bacterial and water- or food-borne.

7. Amoebic dysentery is caused by

   1. Shigella
   2. Giardia only
   3. Hepatitis A virus
   4. Entamoeba histolytica
   Answer

   D. Entamoeba histolytica

   Entamoeba histolytica is the protozoan cause.

8. Excess fluoride in drinking water causes

   1. Itai-itai disease
   2. Fluorosis
   3. Arsenicosis
   4. Blue baby syndrome
   Answer

   B. Fluorosis

   Fluoride damages teeth and bones.

9. High nitrate in drinking water causes

   1. Minamata disease
   2. Fluorosis
   3. Blue baby syndrome
   4. Cholera
   Answer

   C. Blue baby syndrome

   Nitrate leads to methaemoglobinemia in infants.

10. Minamata disease was caused by pollution with

    1. Cadmium
    2. Mercury
    3. Arsenic
    4. Lead
    Answer

    B. Mercury

    Mercury poisoning hit Minamata in Japan.

11. Itai-itai disease is linked to

    1. Nitrate
    2. Fluoride
    3. Mercury
    4. Cadmium
    Answer

    D. Cadmium

    Cadmium poisoning caused this disease.

12. Carbon monoxide is dangerous because it

    1. Damages the ozone layer
    2. Binds with haemoglobin and reduces oxygen supply
    3. Increases blood sugar
    4. Causes acid rain
    Answer

    B. Binds with haemoglobin and reduces oxygen supply

    It forms carboxyhaemoglobin.

13. The only genetically modified crop approved for commercial cultivation in India is

    1. Golden rice
    2. Bt maize
    3. Bt cotton
    4. Bt brinjal
    Answer

    C. Bt cotton

    Bt cotton is the lone approved GM crop.

14. Bt cotton carries a gene from

    1. Bacillus thuringiensis
    2. Escherichia coli
    3. Rhizobium
    4. Agrobacterium only
    Answer

    A. Bacillus thuringiensis

    It makes a Cry protein toxic to bollworm.

15. Which body approves the release of genetically modified organisms in India?

    1. National Green Tribunal
    2. Genetic Engineering Appraisal Committee
    3. Planning Commission
    4. Pollution Control Board
    Answer

    B. Genetic Engineering Appraisal Committee

    GEAC works under the Environment Ministry.

16. The Cartagena Protocol deals with

    1. Wetlands
    2. Whaling
    3. Biosafety
    4. Ozone depletion
    Answer

    C. Biosafety

    It regulates movement of living modified organisms under the CBD.

17. Jal Jeevan Mission aims to provide

    1. LPG connections
    2. Toilets to every home
    3. Free electricity
    4. Tap water connections to rural households
    Answer

    D. Tap water connections to rural households

    It targets functional household tap connections.

18. The Pradhan Mantri Ujjwala Yojana reduces

    1. Water pollution
    2. Noise pollution
    3. Soil erosion
    4. Indoor air pollution from solid fuels
    Answer

    D. Indoor air pollution from solid fuels

    LPG replaces wood and dung stoves.

19. The Swachh Bharat Mission mainly promotes

    1. Crop insurance
    2. Cyclone shelters
    3. Sanitation and toilet use
    4. Rural roads
    Answer

    C. Sanitation and toilet use

    It targeted open defecation and waste.

20. Air Quality Index categories range from Good to

    1. Extreme
    2. Severe
    3. Hazardous
    4. Critical
    Answer

    B. Severe

    The Indian AQI has six categories ending at Severe.

21. The National Clean Air Programme targets mainly

    1. Plastic waste
    2. Groundwater levels
    3. Particulate pollution in cities
    4. Mangrove loss
    Answer

    C. Particulate pollution in cities

    It sets city plans to cut PM levels.

22. Which pollutant penetrates deepest into the lungs?

    1. Sand grains
    2. PM2.5
    3. PM10
    4. Pollen
    Answer

    B. PM2.5

    The finest particles reach deep lung tissue.

23. Which method is standard for disinfecting public water supply?

    1. Aeration
    2. Sedimentation alone
    3. Sieving
    4. Chlorination
    Answer

    D. Chlorination

    Chlorine kills germs.

24. Oral rehydration solution is used for

    1. Dengue
    2. Asthma
    3. Malaria
    4. Diarrhoea
    Answer

    D. Diarrhoea

    It replaces fluids and salts lost in diarrhoea.

25. Gambusia fish is used to control

    1. Water hyacinth
    2. Sandflies
    3. Mosquito larvae
    4. Algae
    Answer

    C. Mosquito larvae

    It eats mosquito larvae, a biological control.

26. Scrub typhus is spread by

    1. Housefly
    2. Chigger mites
    3. Rat flea
    4. Culex mosquito
    Answer

    B. Chigger mites

    Larval mites carry Orientia tsutsugamushi.

27. Japanese encephalitis virus is spread by

    1. Tick
    2. Aedes mosquito
    3. Sandfly
    4. Culex mosquito
    Answer

    D. Culex mosquito

    Pigs are an amplifier host and Culex spreads it.

28. Leptospirosis commonly spreads after floods through

    1. Airborne dust
    2. Water contaminated by animal urine
    3. Sandfly bites
    4. Mosquito bites
    Answer

    B. Water contaminated by animal urine

    Leptospira bacteria spread via infected urine in water.

29. Which of these is a vector-borne disease?

    1. Chikungunya
    2. Hepatitis A
    3. Cholera
    4. Typhoid
    Answer

    A. Chikungunya

    Chikungunya is spread by Aedes mosquitoes.

30. Which of these is a water-borne disease?

    1. Dengue
    2. Kala-azar
    3. Hepatitis A
    4. Malaria
    Answer

    C. Hepatitis A

    Hepatitis A spreads by contaminated water.

31. Climate change affects health by

    1. Increasing ozone
    2. Spreading vector-borne disease to new areas
    3. Removing all infections
    4. Reducing heat stress
    Answer

    B. Spreading vector-borne disease to new areas

    Warmer, wetter conditions extend vector ranges.

32. Arsenic in groundwater is best known to cause health problems in

    1. Rajasthan desert only
    2. The Western Ghats
    3. The Ganga delta region
    4. Lakshadweep
    Answer

    C. The Ganga delta region

    Arsenicosis is common in the Ganga delta.

33. The Bhopal gas tragedy involved the leak of

    1. Sulphur dioxide
    2. Carbon monoxide
    3. Chlorine
    4. Methyl isocyanate
    Answer

    D. Methyl isocyanate

    MIC was the leaked gas.

34. Biosafety rules mainly guard against

    1. Risks of GMOs to health and environment
    2. Floods
    3. Drought
    4. Soil salinity only
    Answer

    A. Risks of GMOs to health and environment

    They address allergies, gene flow and harm to non-target species.

35. Prevention by clean water, sanitation and vaccination is called

    1. Rehabilitation
    2. Primary prevention
    3. Tertiary prevention
    4. Secondary prevention
    Answer

    B. Primary prevention

    These steps stop disease before it starts.

36. Statements about vectors: 1. Aedes aegypti bites mostly by day. 2. Anopheles bites mostly at night.

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    C. Both 1 and 2

    Both are correct.

37. Statements: 1. Malaria is a water-borne disease. 2. Cholera is a water-borne disease.

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    B. 2 only

    Malaria is vector-borne.

38. Statements about Bt cotton: 1. It contains a gene from Bacillus thuringiensis. 2. It is the only commercially approved GM crop in India.

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    C. Both 1 and 2

    Both are correct.

39. Statements about GEAC: 1. It works under the Environment Ministry. 2. It hears environment cases as a tribunal.

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    A. 1 only

    The National Green Tribunal hears cases.

40. Statements about fluoride and nitrate: 1. Fluoride causes fluorosis. 2. Nitrate causes fluorosis.

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    A. 1 only

    Nitrate causes blue baby syndrome.

41. Statements about the Cartagena Protocol: 1. It is under the Convention on Biological Diversity. 2. It deals with biosafety.

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    C. Both 1 and 2

    Both are correct.

42. Statements about indoor air pollution: 1. Solid cooking fuels cause it. 2. LPG under Ujjwala helps reduce it.

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    C. Both 1 and 2

    Both are correct.

43. Statements about carbon monoxide: 1. It reduces oxygen carried by blood. 2. It causes fluorosis.

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    A. 1 only

    It does not cause fluorosis.

44. Statements about Jal Jeevan Mission: 1. It targets household tap connections. 2. It is meant for toilets.

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    A. 1 only

    Toilets belong to the Swachh Bharat Mission.

45. Statements about dengue: 1. It is caused by a virus. 2. It is spread by Culex.

    1. 1 only
    2. 2 only
    3. Both 1 and 2
    4. Neither 1 nor 2
    Answer

    A. 1 only

    Dengue is spread by Aedes.