How did the development of the cities influence the ecology and environment in late 19th century?

How did the development of the citiesinfluence the ecology and environment in late 19th century? Explain your answer by giving the examples of Calcutta.
Ans. Cities developed everywhere at the expense of ecology and environment. Natural features were transformed for the establishment of factories, housing and other institutions.
The following examples justify the fact
(i) In Calcutta, coal was used in industries and steam engines. The high content of ash in Indian coal became a great problem.
(ii) As the city was built or marshy land, the resulting fog in winter combined with smoke generated thick black smog. It created a high level of pollution.
(iii) The inhabitants of Calcutta used coal, wood and dung as fuel in daily life. It produced dense smoke, which made the air poisoning and caused many diseases like respiratory and skin diseases.
(iv) Calcutta was the centre of manufacturing and its industries were mainly developed at the bank of river Ganga (Hoogly). The waste products from these industries polluted the water and air.
(v) Due to industrialisation and urbanisation, noise pollution was very common in Calcutta. All these factors were very harmful to environment and ecology. In 1863, Calcutta became the first Indian city to get Smoke Nuisance Legislation.