The researchers developed a method to group regions in India based on how much and how rainfall varies over time. They used data from 1901 to 2013 to identify ten distinct regions with unique rainfall patterns. By considering both the amount of rainfall and how it changes seasonally, they found new patterns emerging in Central India and differences in the Western Himalayas due to topography. They also discovered changes in monsoon rainfall patterns in different regions over time, like an increase in western India and a decrease in the north-central region after the 1980s.