VAPI, India — Factory owners in this city on the western coast of India have been fuming, railing, and arguing for years against a single troublesome number: the pollution index used by the Ministry of Environment and Forests, which identified Vapi as an area so badly contaminated that any further industrial growth there was banned.

They finally got some good news in early June, about two weeks after Narendra Modi was sworn in as prime minister. The new officials at the ministry told them that the pollution index would be revised — and in the meantime, Vapi’s chemical and pesticide factories were again free to expand, and to snap at China’s share of the global chemical export market.

Rightly so, said Harshad Patel, standing outside the plant where he works. The air had an acrid-sweet smell, and reddish-brown effluent was gushing from a treatment plant down the road at a rate of 55 million gallons a day into the Daman Ganga River, but Mr. Patel looked untroubled. “Clean India is fine — we also like clean India,” he said. “But give us jobs.”

Indian industries have often complained that convoluted environmental regulations are choking off economic growth. As a candidate, Mr. Modi promised to open the floodgates, and he has been true to his word. The new government is moving with remarkable speed to clear away regulatory burdens for industry, the armed forces, mining and power projects.