National Aeronautics and Space Administration on Tuesday released an animated map showing that between December 1 and 2, Chennai received more rainfall in 24 hours than on any day since 1901. The space agency’s map provides satellite-based estimates of rainfall over south-eastern India, reported PTI. NASA’s Earth Observatory said the monsoon figures were already well above normal before the flooding intensified in the state. More than 420 people have been killed so far in the state.

The highest amount of rain recorded this season is 500 mm, in an area “just off the south eastern coast”, according to Hal Pierce, NASA’s Goddard Space Flight Centre scientist. The report said Indian meteorologists attributed the heavy rain to a strong north-east monsoon. During the season, the winds blow over the Bay of Bengal and pick up a great deal of moisture from the sea before exploding over the southern and eastern areas of India. The rain was also amplified by “record-warm seas” and the “long-distance effects of El Nino”, said NASA.