Bowing to intense public pressure, the Chesapeake Energy Corporation says it will not drill for natural gas within the upstate New York watershed, an environmentally sensitive region that supplies unfiltered water to nine million people.

The reversal seems to signal a more conciliatory tone from the gas industry, which is facing mounting opposition in New York to its drilling practices. The decision also increases the pressure on state regulators to reverse their decision to allow drilling within the watershed.

“We are not going to develop those leases, and we are not taking any more leases, and I don’t think anybody else in the industry would dare to acquire leases in the New York City watershed,” Aubrey K. McClendon, the chief executive officer at Chesapeake Energy, said in an interview on Monday in Fort Worth. “Why go through the brain damage of that, when we have so many other opportunities?”

He spoke on the eve of the first scheduled hearing on proposed state rules governing the drilling, on Wednesday in Loch Sheldrake in Sullivan County.