The top leaders of China and India, two of the world's top emitters of greenhouse gases

The top leaders of China and India, two of the world's top emitters of greenhouse gases, aren't planning to attend this month's United Nations summit on climate change, according to a diplomat at the UN.

President Xi Jinping of China and Indian Prime Minister Narendra Modi have told UN Secretary General Ban Ki-moon they won't be at the day-long meeting of world leaders on Sept. 23, the person said, requesting not to be identified discussing the leaders' plans. That deals a blow to a gathering meant to lay the groundwork for a global agreement to reduce carbon dioxide, which is blamed for global warming.

"The issue for us is really on the commitments that countries will bring and the secretary general expects member states to come with strong and bold commitments on climate change," Ban's spokesman Stephane Dujarric said today in New York. He said he has nothing to add when asked about the leaders' attendance.

China is the world's top greenhouse-gas emitter, and India is third, after the U.S., according to World Bank data. Together China and India account for nearly a third of total emissions, and their carbon footprint is growing while it remains flat in the U.S. and Europe.