Acid rain is caused by the pollution of environment by

Acid rain is primarily caused by the release of sulfur dioxide (SO2) and nitrogen oxides (NOx) into the atmosphere [2]. These pollutants are largely emitted from the burning of fossil fuels in motor vehicles, power plants, and industrial processes [3]. Once in the atmosphere, these gases react with water, oxygen, and other chemicals to form sulfuric acid and nitric acid [4]. These acids then precipitate to the ground as wet deposition (rain, snow, or fog) or dry deposition [3]. While unpolluted rain is slightly acidic (pH ~5.6) due to dissolved carbon dioxide forming weak carbonic acid, acid rain typically has a much lower pH, often between 4.2 and 4.4 [4]. Nitrous oxide (N2O) and nitrogen dioxide (NO2) are key components of the nitrogen oxide group that contributes to this environmental acidification [1].

Sources

1. [1] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 6: Environmental Degradation and Management > Acidification > p. 8
2. [2] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 6: Geomorphic Movements > Anthropogenic Solution Weathering > p. 90
3. [3] https://www.epa.gov/acidrain/what-acid-rain
4. [4] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 5: Environmental Pollution > 5.I5. ACID RAIN > p. 101