India, May 27 -- On Monday, the city woke up to a heavy downpour that caught it completely off guard as the India Meteorological Department (IMD) had issued a yellow alert, the second mildest in its colour code, for the day. The weather bureau on Sunday had also stated that the onset of the monsoon in Mumbai was expected by Wednesday.

IMD maintained the yellow alert for May 26 till 8.30 am when the weather station updates the forecasts. It upgraded it to an orange alert at 9.39 am. Less than three hours later, at 12.30pm, it further upgraded the warning to a red alert, indicating extreme rains.

An official from IMD Mumbai stated that the yellow alert was upgraded to orange after the Colaba observatory logged more than 79 mm of rainfall....