The torrential monsoon rains paralyzed India's financial capital Mumbai for a third day Thursday as the streets turned into rivers and people waded through waist-deep waters.
By Thursday the city had received almost 300mm of torrential rain in the last four days, reported the Hindustan Times.
Public transport stopped and thousands of commuters were stranded in their offices overnight.
India's monsoon season runs from June through September.
Since its start this year devastating floods have killed more than 1,000 people across South Asia and affected close to 40 million in northern India, southern Nepal and northern Bangladesh.
The rains have led to wide-scale flooding in a broad arc stretching across the Himalayan foothills in the three countries, causing landslides, damaging roads and electric towers and washing away tens of thousands of homes and vast swathes of farmland, Associated Press reported.
According to the Times of India a 117-year-old building also collapsed in Mumbai early Thursday in the deluge leaving at least nine people dead and over 20 believed trapped.
On Thursday morning rescue workers were looking for survivors.
Surrounding houses were also damaged when the building collapsed.
The UK's Guardian reported that the storm reached Pakistan on Thursday, lashing the port city of Karachi.
Local TV footage showed streets were already submerged as the country's meteorological department forecast that the rains would continue for three days in various parts of Sindh province, where authorities closed schools as a precaution.
Windstorms and rain are also expected in the south-western Baluchistan and eastern Punjab provinces.
The meteorological department said rains were also expected in the capital, Islamabad, and in Kashmir.
One third of Bangladesh was believed to be underwater and in Nepal, where 150 people have died, the UN called it the worst flooding in a decade, the Guardian reported.