MUMBAI, Aug. 22 -- When heavy rains lashed the city earlier this week, causing waterlogging in several areas, the BMC was prepared in advance, armed as it was with forecasts from the Indian Institute of Technology (IIT) Bombay in addition to those disseminated by the India Meteorological Department (IMD). IIT-B and IMD have collaborated on a project that puts out localised weather forecasts, predicting rainfall and waterlogging in specific areas. As western disturbances and a depression off the coast of Andhra Pradesh was expected to trigger an episode of heavy rainfall, Mumbai's weather bureau updated its forecast at 3.30am on August 18. However, the BMC had received alerts from IIT Bombay a day prior. "IIT-Bombay sent a localised forecast on August 17," said Abhijit Bangar, additional municipal commissioner (Projects). "It marked areas that were expected to receive over 200 mm of rainfall." Climate change has changed monsoon patterns, so out of 120 days, there are at least three to four days when the city receives extremely heavy rainfall. "A localised forecast stating which area will receive how much rain helps to tackle the situation better than a blanket forecast of heavy rains," said Bangar. "The IIT-B model also gave data on the amount of waterlogging expected in each area." All the city's 24 wards have an additional dewatering pump that can be deployed based on the situation. "The forecasts received were sent to all the wards, which could then take a call on where and when to deploy the pumping stations based on the requirement," said Bangar. Depending on the waterlogging alerts, civic officials were able to deploy staff for help. The forecasts were made from a model named mumbaiflood.in, which uses AI and machine learning to read and process the data from doppler radars set up by the IMD department in Mumbai. "The system gives a real-time forecast of 90 minutes as soon as the doppler receives the signal," said Subimal Ghosh, head of the Centre for Climate Studies at IIT. The model created by Puja Tripathy, a PhD student, was launched on an experimental basis, and is open to everyone. "The portal is live and in due course people will be able to check the weather and water logs before leaving the house," said Ghosh. The BMC is now collaborating with IIT-B to identify new flooding hotspots around the city and find measures to mitigate this. In the past three days, the city crossed the average rainfall mark of 566 mm and logged over 890 mm. Several individual areas also crossed the 300 mm mark, causing severe waterlogging....