The monsoon trends that India is witnessing with every passing year show that the nature of monsoon rains has changed over a period of time. The Southwest monsoon season, as it is geographically called, extends from June 1 to September 30. However, these four months do not witness the same intensity of rains throughout the period, instead, even a few days and weeks of variations are observed in the rain pattern. The data provided by IMD to the Indian Express shows that in many cities of the country entire rainfall of the season occurs in a small window of time.
According to the data analysis by IE, in 22 cities of sizeable population, 95 per cent of monsoon precipitation occurs over three days to 27 days on average. For example, Delhi receives 95 percent of its monsoon rainfall in just 99 hours (50 percent in 33 hours on an average). On the other hand, India’s financial capital Mumbai, which is situated on the western part of the country, receives 50 percent of its annual rainfall in 134 hours (just five and a half days on an average).
Ahmedabad in Gujarat receives average seasonal rain of 66.3 cm in 46 hours and 95 percent in 143 hours. Jaipur and Ajmer in Rajasthan receive 95 percent monsoon rains in about 90 hours. Southern city Bengaluru gets 95 percent showers of rain in just five days. While UP Capital Lucknow receives 95 percent monsoon rainfall in five days.
Underlining the fact that how planning is important considering the impact of rains, K Saikranthi, Inspire faculty at the Indian Institute of Science Education and Research (IISER), Tirupati, said, “This is very important for city and town planning. If you are getting more rain within a short duration, it affects urban flooding”. Highlighting the importance of studying extreme weather as it directly affects the people, she added, “If extreme weather events are more, water will get accumulated which will lead to floods. It is very important to study extreme weather events to understand what they lead to, since it affects the public”.
Urban flooding has been a concern for many Indian cities every year. In recent years, for example, major urban flooding was seen in Mumbai (2005) and Chennai (2015). Cities are paralysed every year during the monsoon and loss of life and property are witnessed.
However, the changing nature and fluctuation in monsoon rains have been discussed thoroughly by policy makers of the country. Dr M Rajeevan, who is the Secretary of Union Ministry of Earth Sciences, said that this could be one of the indications of the climate change. “The decreasing trend of average rain hours could be an indication of climate change, it is not a direct link, but it could be interpreted as change caused due to global warming,” he said.
