Long-term variations of surface air temperature at major industrial cities of India

Local temperature is one of the major climatic elements to record the changes in the atmospheric environment brought about by industrialization and urbanization. Long-term variations of seasonal and annual surface air temperature at six major industrial cities of India (Calcutta, Bombay, Madras, Bangalore, Pune and Delhi) have been studied, using data for the past 86 to 112 yr. Comparative analysis of the temperature data of six nonindustrial stations has also been done. The long-term change in the temperature has been evaluated by linear trend. Calcutta, Bombay and Bangalore have shown significant warning trend, while Delhi has shown a cooling trend. The trends at Madras and Pune are not significant. The nonindustrial stations did not show significant trends. In general, there was either a cooling tendency or cessation of warming, after the late 1950s at most of the industrial cities.