State any three causes of air pollution in Calcutta in the 19th century.
CALCUTTA had a long history of air pollution :
- High levels of pollution were a consequence of the huge population that depended on dung and wood as fuel in their daily life.
- The main polluters were the industries and establishments that used steam engines run on coal. The railway line introduced in 1855 brought a new pollutant into the picture - Coal from Raniganj. The high content of ash in Indian coal was a problem.
- In 1920, the Rice Mills of Tolly gunge began to burn rice husk instead of coal leading to air filled with black soot falling like drizzling rain.