"The city and surrounding areas received about 80-90mm rain in about three hours from 7 pm due to low pressure and surface winds across the region," a senior meteorological official told IANS.
Though the southwest monsoon is still a week away from entering the state, the official said the city had been blessed with pre-monsoon showers since a fortnight after a prolonged and hot summer.
"The pre-monsoon showers have been precipitated by a low pressure off the Bay of Bengal, which led to formation of thick clouds over the coastal, north and south interior areas of the state and leading to widespread rains," the official asserted.
The downpour, however, caught thousands of people returning home from work or shopping unawares in the city. "It's a welcome relief to have good rains after a scorching summer. But the city, its roads, drainage and civic agencies are ill-equipped to face the situation due to pathetic infrastructure and basic amenities stretched out," D.P. Muralidhar, a state official lamented after managing to reach home in southwest suburb in a bus that got caught in the city's notorious grid lock.
The Bruhat Bangalore Mahanagara Palike (BBMP) received hundreds of calls from across the city for relief as rain water and drainage water entered their houses and parking basements in apartments.
Even the state fire brigade received several calls from people stranded in submerged localities and slums for rescuing them.
With around 4.5 million vehicles, including two-wheelers, cars, buses, trucks and other types of travel mode clogging main thoroughfares, flyovers, traffic junctions and service roads, traffic came to a standstill even in the central business district and upscale suburbs in eastern, western and southern areas.
"The worst-affected were the floating population and commuters leaving the city for a weekend break from the inter-state bus stands at Majestic and Shantinagar and the city railway station," a police official said after deploying more traffic constables to regulate the chaotic traffic in many localities across the city of about 10 million denizens, including two-three million of them from across the state or country.