Eleven central trade unions have backed the strike call, posing a fresh challenge to Prime Minister Manmohan Singh and his leftist administration, which had called on the unions to call off the show of force. "This is an historic occasion. For the first time all the big trade unions have come together to protest the anti-labour polices of the government," All India Trade Union Congress general secretary Gurudas Dasgupta told AFP. Among the unions' demands are a national minimum wage, permanent jobs for 50 million contract labourers and greater government efforts to rein in the rising cost of living. "We gave the government ample opportunity to discuss these issues. Now striking is the only option before us," Dasgupta said. "We are fighting for our rights against a government that is anti-people," he added. Singh's government, already tainted by a series of high-profile corruption scandals, has struggled to keep inflation in single digits at a time when the economy is growing at its slowest rate for three years. Transport, banking and postal services were all expected to be hit by the 24-hour strike that began midnight Monday. In Kolkata, a traditional trade union stronghold, most bank branches, shops and other businesses were closed, with taxis and rickshaws staying off the streets.