✅ Answer: A) 1 and 2 onlyStatements 1 and 2 are correct. PM2.5 refers to particulate matter with aerodynamic diameter less than 2.5 micrometres. Due to their tiny size, PM2.5 particles can penetrate deep into the lungs (alveoli) and even enter the bloodstream, causing respiratory and cardiovascular diseases. Statement 3 is incorrect — PM2.5 can be both a primary pollutant (directly emitted from vehicles, industries, biomass burning) and a secondary pollutant (formed in the atmosphere from reactions of SO₂, NOₓ, and ammonia). Secondary PM2.5 formation is a major contributor to Delhi’s winter pollution.

✅ Answer: A) 1, 2 and 3All three statements are correct. Photochemical smog (Los Angeles type) is formed when NOₓ and VOCs react in the presence of sunlight to produce ozone, PAN, and other oxidants — hence it is an oxidising type of smog. PAN (Peroxyacetyl Nitrate) is a key component that causes eye irritation and damages plants. It occurs in warm, sunny conditions. Classical/London smog is different — it is formed by SO₂ + fog + smoke in cold, humid conditions and is a reducing type. Photochemical smog is a major problem in cities like Delhi, Mumbai, and Los Angeles.

✅ Answer: A) 2014The Namami Gange Programme was launched in 2014 with a budget of ₹20,000 crore. It is an integrated conservation mission to accomplish the twin objectives of effective abatement of pollution and conservation and rejuvenation of the Ganga river. Key components: sewage treatment plants (STPs), river-front development, ghats and crematoria, afforestation, biodiversity conservation, and public awareness. The National Mission for Clean Ganga (NMCG) is the implementing agency. Ganga was declared India’s National River in 2008. The Ganga Action Plan (GAP) was the earlier initiative (1985) but was largely unsuccessful.

✅ Answer: A) Fluorosis — dental and skeletal damageExcess fluoride in drinking water (above 1.5 mg/L) causes fluorosis. Dental fluorosis causes mottling and discolouration of teeth. Skeletal fluorosis causes bone deformities, joint pain, and crippling. Fluoride-affected states in India: Rajasthan, Andhra Pradesh, Telangana, Gujarat, Tamil Nadu. Blue baby syndrome (methaemoglobinaemia) is caused by excess nitrates in water — affects infants. Arsenicosis is caused by arsenic in groundwater — common in West Bengal and Bangladesh. Minamata disease is caused by mercury poisoning. WHO permissible limit for fluoride in drinking water is 1.5 mg/L.

✅ Answer: B) 40%The National Clean Air Programme (NCAP) was launched in January 2019 by the Ministry of Environment, Forest and Climate Change (MoEFCC). It targets a 40% reduction in PM2.5 and PM10 concentrations by 2026 (base year 2017). NCAP covers 131 non-attainment cities (cities that have not met National Ambient Air Quality Standards for 5 consecutive years). Key measures: city-specific action plans, real-time monitoring, source apportionment studies, and public awareness. CPCB is the nodal agency. The programme was initially set for 2024 but extended to 2026.

✅ Answer: A) NitratesBlue Baby Syndrome (methaemoglobinaemia) is caused by excess nitrates in drinking water. Nitrates are converted to nitrites in the gut of infants (not adults). Nitrites react with haemoglobin to form methaemoglobin, which cannot carry oxygen — the baby’s skin turns bluish due to oxygen deprivation. Nitrates enter groundwater from excessive use of nitrogen fertilisers and sewage. WHO limit for nitrates in drinking water is 50 mg/L. This is a significant problem in agricultural areas with heavy fertiliser use. Fluorides cause fluorosis; arsenic causes arsenicosis; lead causes neurological damage.

✅ Answer: A) Sulphur Dioxide (SO₂) and Nitrogen Oxides (NOₓ)Acid rain is caused when SO₂ and NOₓ react with water vapour in the atmosphere to form sulphuric acid (H₂SO₄) and nitric acid (HNO₃). Normal rain has pH of 5.6 (slightly acidic due to CO₂); acid rain has pH below 5.6. Effects: damages forests (especially conifers), acidifies lakes and rivers (kills fish), corrodes buildings and monuments (marble cancer — damages Taj Mahal), damages crops. CO₂ and CH₄ are greenhouse gases (cause global warming, not acid rain). CFCs deplete the ozone layer. The Taj Mahal Protection Zone restricts industries to prevent acid rain damage.

✅ Answer: C) 3rdIndia is the 3rd largest generator of e-waste in the world, after China and the USA. India generates about 3.2 million metric tonnes of e-waste annually. E-waste contains toxic materials like lead, mercury, cadmium, chromium, and brominated flame retardants. The E-Waste Management Rules 2016 (amended 2022) introduced Extended Producer Responsibility (EPR) — producers, importers, and brand owners must collect and recycle e-waste. The informal recycling sector handles most e-waste in India using unsafe methods (acid baths, open burning), causing serious health hazards for workers. Maharashtra, Tamil Nadu, and Uttar Pradesh are the top e-waste generating states.

✅ Answer: A) Water (Prevention and Control of Pollution) Act 1974The Central Pollution Control Board (CPCB) was established in 1974 under the Water (Prevention and Control of Pollution) Act 1974. The Air Act 1981 extended CPCB’s mandate to air pollution as well. CPCB is the national body for pollution control — it sets standards, monitors pollution levels, advises the central government, and coordinates with State Pollution Control Boards (SPCBs). SPCBs were also established under the Water Act 1974 at the state level. The EPA 1986 is the umbrella legislation that came later. CPCB headquarters is in New Delhi.

✅ Answer: A) Discharge of heated water from power plants and industries, which reduces dissolved oxygenThermal pollution occurs when industries (especially thermal power plants and nuclear power plants) use water for cooling and discharge it back into water bodies at a higher temperature. Warm water holds less dissolved oxygen (DO) — this stresses or kills aquatic organisms. It also accelerates the metabolism of aquatic organisms, disrupts breeding cycles, and makes water bodies more susceptible to algal blooms. Thermal pollution is a significant issue near large power plants on rivers. Solutions include cooling towers, cooling ponds, and spray ponds to reduce the temperature of discharge water before releasing it.