Global insurer Chubb Ltd. is tightening its requirements on insurance policies for oil-and- gas producers, demanding that they reduce emissions of methane, a potent greenhouse gas.Chubb which is a top-10 insurer in the worldwide oil-and-gas market by premium volume, will also stop underwriting projects in areas designated as protected by state, provincial or national governments, effective immediately.The company has been under pressure from climate activists, who have targeted banks and insurers to cut off funding and insurance coverage for fossil-fuel companies. Chubb’s actions fall short of their demands to quit sales to oil and gas producers.Chubb Chief Executive Evan Greenberg said in an interview that the carrier’s move wasn’t motivated by activists’ pressure. The insurer’s plan is a “science-based and technical way” to help with carbon reduction, he said. As an underwriter, Chubb will be able to verify that clients are taking the required steps. “If not, then we won’t underwrite them,” he said.