Japanese Prime Minister Yukio Hatoyama called on his Indian counterpart on Saturday to make an international commitment on climate change, saying it was vital for a U.N. deal due in Copenhagen in December. Hatoyama, who took office last month after a landslide election victory, has pledged Japan -- the world's fifth biggest emitter of greenhouse gases -- will cut emissions 25 percent by 2020 and hopes emerging nations like China and India will also sign up to an ambitious global deal. "India's commitment is indispensable for the success of Copenhagen and I hope it will make an international commitment based on their steps taken domestically," Hatoyama told Indian Prime Minister Manmohan Singh, according to a Japanese government official.