Several studies across the world, including in India, show that urbanization may be influencing precipitation, in many cases by intensifying extreme rainfall events. 

The trend of increasingly intense rainfall events over urban areas in India was first identified in a 2010 study led by Isro's Chandra Kishtawal and US scientist Dev Nigoyi. A more recent study from IIT-Bombay looking at 42 regions across the country found that while urbanization does not play a big role in rainfall in north India, the effect was prominent in the western and central regions. 

To confirm the role of urbanization, and eliminate other factors, IIT researchers Hiteshri Shastri, Subimal Ghosh, Subhankar Karmakar and Supantha Paul looked closely at the Mumbai urban area. They compared the city's rainfall records with the adjoining rural district of Alibaug for 1969-2005. 

Both places are subject to the same weather systems, the same "circulation patterns and moisture levels", said Ghosh, an associate professor with the IIT's department of civil engineering. Yet, the researchers found, Mumbai saw a significant increase in extreme rainfall days. "When it comes to high rainfall, urbanization seems to play a factor in intensifying it," he said.