Shopkeepers, traders and laborers blocked railway lines and closed markets across India on Thursday in a nationwide day of protest against reforms allowing market entry by foreign supermarkets.

Opposition parties and trade unions called the strike after Prime Minister Manmohan Singh last week announced a raft of reforms designed to revive India's slowing economy, a move that has sparked a furious backlash.

Kolkata, Bangalore and Chennai were among cities most affected by the 24-hour strike, with the majority of shops, factories, schools and offices shut down for the day.

Protests were held across India with effigies of Singh burnt by demonstrators in Bangalore, and strikers blocking some national highways and major rail routes.

But the response to the strike appeared mixed with many shops in New Delhi still open, and Mumbai, largely untouched after local political parties declined to support.

Many small business owners and workers in India fear that the arrival of large-scale foreign supermarket chains will lead to drastic job losses as supply chains and shopping habits are transformed.

"I am closed for today like most people," said Gautham Bhalla, standing outside his small hardware shop in south Delhi's normally bustling Bhogal market.

"This strike has my total support - we will lose business if these big stores come."

Singh has been buffeted by the reaction to the reforms and a sharp rise in diesel prices, with a key West Bengal-based coalition party quitting the government and demanding the policies be reversed.

The Trinamool party said on Tuesday it had decided to withdraw support from the Congress-led ruling coalition in a move analysts said could cause the government to fall before the next elections due in 2014.

Many schools in India were closed because of the strike, but most government offices remained open.

The Confederation of All India Traders claimed that 50 million businesses were participating in the protest against.

The arrival in India of chains such as Walmart, Tesco and Carrefour is expected to herald a consumer revolution with shoppers moving from small, neighborhood stores to large, out-of-town supermarkets.