Floods caused by monsoon rains forced the closure of a natural gas plant and petrochemical factories in western India, where scores of people have been killed and hundreds of thousands displaced in recent days, according to reports Wednesday.

Heavy rains over the past two weeks have swollen rivers and flooded houses, forcing some 650,000 people from their homes in southern Andhra Pradesh state and the western states of Gujarat and Maharashtra. At least 145 people have died in the past week.

CountryWatch: India

Several low-lying areas in Bombay, India's financial hub and Maharashtra's capital, remain flooded, and Indian television channels broadcast footage of people struggling through murky waters in villages and cities while air force helicopters and naval boats tried to rescue those stranded.

Nearly 3.5 million people living in and around the city of Surat in Gujarat state were affected by the floods, the Press Trust of India news agency reported. More than 80 percent of the city was submerged by water, the agency quoted Police Commissioner Sudhir Sinha as saying.

The Business Standard newspaper said several energy and fertilizer companies scaled back production after the closure of gas and petrochemical plants in the city of Hazira in Gujarat.

Oil & Natural Gas Corp. said it closed a plant in the city that supplies most of the gas used in northern India, while Reliance Industries also closed several petrochemical plants.

Once the waters recede, restoring gas supplies could take up to a week, the Business Standard said, quoting unnamed officials at the Gas Authority of India Ltd.

Indian Prime Minister Manmohan Singh planned to visit Maharashtra and Gujarat on Thursday. Both states have been among the hardest hit by this year's monsoon, which runs from June to September.

Across India, the rains have killed at least 527 people this year, with most drowning in floods, being crushed by landslides or collapsed houses, or getting electrocuted. However, many areas don't keep accurate death tolls, and the total number of people killed is likely much higher.