Acid Rain  acidic rainfall, caused principally by the release of sulphur dioxide (SO₂) and oxides of nitrogen into atmosphere. Sulphur dioxide is formed from the burning of fossil fuels, such as coal, that contain high quantities of sulphur; nitrogen oxides are contributed from various industrial activities and from car exhaust fumes. Acid rain is one of the most critical environmental concerns of the world today, especially because Bangladesh is becoming more and more industrialized and the streets are becoming crowded with motorized vehicles.

Acid rain falling into rivers and lakes kills eggs of fish and fish fries. The chain reaction touches man and other life forms. Acid rain leaches essential plant nutrients like calcium, magnesium, potassium and sodium from the underlying soil and organic matter. It prevents bacteria from decomposing leaf litter, kills earthworms and other beneficial soil microorganisms, and affects seed germination. It also releases toxic amounts of metal to be absorbed by roots and water supplies.

The cities of Dhaka, Khulna and Chittagong and the industrial belts around these cities are the real agents of acid rain in this country, and the neighbouring country India is supplying plenty of sulphuric and nitric acids from across the borders from their industrial and power plants. There are signs of decline in the fertility of organisms and the growth of agricultural produces. [M Shamsul Islam and Quamrun Nessa Begum]