Acid rain is caused by increase in the atmospheric concentration of:

Explanation

Acid rain is rainfall and other forms of precipitation with a pH of less than 5. Acid rain is caused by the large scale emission of acidic gases into the atmosphere from thermal power plants, industries and automobiles. The common ones are sulphur dioxide, nitrogen oxides (NOx), volatile organic carbons (VOCs), and hydrogen chloride. Sulphur dioxide and nitrogen oxides are changed in the atmosphere into sulphuric acid and nitric acid by combining with oxygen and water, which then fall on the earth in the form of acid rain.