(i) Calcutta or Kolkata had a long history of air pollution. Its inhabitants inhaled grey smoke, particularly in the winter. Since the cry was built on marshy land, the resulting fog combined with smoke to generate a thick black smog. (ii)Burning of dung and wood fuel were the main sources of air pollution. (iii) Colonial authorities at first intended to clear I the place of miasmas, or harmful vapours, but the railway lines introduced in 1855, brought a dangerous new pollutant into the picture - coal from Raniganj. The high content of ash in the Indian coal was a problem Many pleas were made to banish the dirty mills from the city, but without any results, (iv) Calcutta (Kolkata) was the first city to get smoke nuisance legislation in 1863. (v) The inspectors of the Bengal Smoke Nuisance Commission finally managed to control the industrial smoke. Controlling domestic smoke, however, was for more difficult.