Where does acid rain naturally occur?

Acid rain is most prevalent where emissions of sulphur dioxide and nitrogen oxide are high, especially in industrial countries, it can occur anywhere on Earth as winds blow emissions many miles from their sources.

Go through the detailed information on Acid Rain in the given link.

Further Readings – 

1. Air Pollutants – Classification, Sources and Impacts
2. Rainfall Distribution in India
3. Montreal Protocol
4. Greenhouse Gas