NEW DELHI Veteran social activist Anna Hazare was detained by police at his home on Tuesday to prevent him from defying authorities with a fast to the death to force tougher laws against corruption, media reported. Police denied the septuagenarian permission on Monday to fast near a cricket stadium because he had failed to meet certain conditions, including ending his fast in three days and ensuring not more than 5,000 people took part. "Police have detained us," Arvind Kejriwal, an aide to Hazare, told NDTV broadcaster before being taken away by plainclothes police in a white car. Local media said police took Hazare into custody to prevent a breakdown in law and order in the capital as thousands of followers were due to take part in the fast. Hazare has become a serious challenge for Prime Minister Manmohan Singh's government, challenging it over its failure to tackle corruption in Asia's third largest economy.