May

May is the calendar's labour-and-family stretch, with the Red Cross movement's founder's birthday anchoring one of its best-known days.

• 1 May — International Labour Day (May Day), commemorating the 1886 Haymarket affair in Chicago, where workers striking for an eight-hour working day clashed with police — observed globally (including as a public holiday in many Indian states) to celebrate the contributions and struggles of the labour movement.
• 3 May — World Press Freedom Day, proclaimed by the UN General Assembly in 1993 following a UNESCO recommendation, marking the anniversary of the 1991 Windhoek Declaration on press freedom and pluralism issued by African journalists in Namibia.
• 4 May — International Firefighters' Day, chosen partly in memory of five firefighters killed in a wildfire in Australia on 2–4 December 1998, and observed to honour firefighters worldwide for their sacrifice.
• 8 May — World Red Cross and Red Crescent Day, marking the birth anniversary of Henry Dunant (born 8 May 1828), the Swiss businessman whose eyewitness account of the aftermath of the Battle of Solferino (1859) led directly to the founding of the International Committee of the Red Cross and, later, the Geneva Conventions.
• 11 May — National Technology Day, marking the date in 1998 that India conducted the Pokhran-II nuclear tests at the Pokhran Range in Rajasthan, under Operation Shakti — chosen specifically to commemorate India's technological self-reliance in strategic and defence science.
• 12 May — International Nurses Day, marking the birth anniversary of Florence Nightingale (born 12 May 1820), the founder of modern nursing, celebrated for her pioneering work caring for wounded soldiers during the Crimean War.
• 15 May — International Day of Families, proclaimed by the UN General Assembly in 1993, reflecting the importance the international community attaches to families as basic units of society.
• 17 May — World Telecommunication and Information Society Day, marking the date in 1865 that the International Telecommunication Union (ITU) was founded (originally as the International Telegraph Union) — one of the oldest international organisations in the world.
• 21 May — Anti-Terrorism Day, observed in India to mark the anniversary of the assassination of former Prime Minister Rajiv Gandhi on 21 May 1991, and to spread awareness against terrorism and violence.
• 24 May — Commonwealth Day (observed on the second Monday in March in the modern Commonwealth calendar — historically 24 May, Queen Victoria's birthday, was the original date before the shift; both dates appear across older and newer reference material, a useful distinction to hold in mind rather than a fixed fact to over-memorise).
• 31 May — World No Tobacco Day, established by the WHO in 1987, to draw global attention to the health risks of tobacco use and to advocate for effective policies to reduce consumption.

Memory hook — "Two founders' birthdays carry the health-and-humanitarian torch": Henry Dunant's birthday (8 May) gives the Red Cross Day, and Florence Nightingale's birthday (12 May) gives Nurses' Day — both days are less than a week apart and both honour a single founding figure's birth date rather than an event or treaty.

Practice Recall: Name the operation under which India's 1998 nuclear tests were conducted, the exact date, and the day it is now commemorated as.