In a memorandum of understanding yesterday in New Delhi, Asia's two biggest polluters from burning carbon-based fuels said they would collaborate on renewable power and energy-efficiency projects. They rejected limits on their emissions proposed by industrialized nations under an international climate accord.

"They're trying to gain leverage going into Copenhagen and show the world they have other options if the global talks break down," said Olav Roenningen, senior analyst at the carbon-markets advisory firm Markedskraft in Arendal, Norway.

The New Delhi accord shows how support may be eroding for a treaty that U.N. negotiators aim to conclude in Copenhagen in December.

Developing nations led by China and India are devising similar regional agreements, citing a failure by wealthier countries, including the United States, to agree to reduce emissions by 2020 by 40 percent from 1990 levels and to share clean-energy technology with poorer countries.

Speculation that countries won't produce a treaty built this month after Yvo De Boer, the top U.N. climate official, said the Copenhagen summit might be "half-baked" unless rich nations agreed to do more to trim gas emissions.

"When India and China take the lead, the rest usually follow," said Michael Mason, director of the conservation program at the Grantham Institute for Climate Change at the London School of Economics. Still, he said, their new accord may be seen "as a ploy to say, 'We're going to go ahead and start dealing bilaterally if we can't come to a multilateral agreement.' "

The accord was signed by Xie Zhenhua, vice minister at China's National Development and Reform Commission, and India's environment minister, Jairam Ramesh.

"We may see even more regional deals like this during the next month before the U.N. climate talks start," Roenningen said.

Ministers from more than 30 African nations agreed in May that measures to adapt to the effects of climate change on agriculture, water supply, forests, and human health should be included in national and regional development plans.

Chinese President Hu Jintao said last month that his country would cut emissions in proportion to economic growth, without outlining specific goals.

China and India together account for about one-fourth of the emissions blamed for global warming. Scientists say the warming leads to rising sea levels and disruptive weather patterns that cause more intense storms and droughts.