A day-long, national strike in India has disrupted air, rail and banking services across the country.
Women demonstrate against the government in northern India
Left-wing trade unions were protesting at the government's economic reforms. It was the first national strike since the Congress party won power in 2004.
Private airlines cancelled flights as airport staff walked out in protest at plans to privatise airports.
Indian communist parties are key supporters of the ruling coalition, but they oppose major economic reforms.
The BBC's Sanjeev Srivastava in Delhi says the government is in a tricky situation as it needs the support of the communists in the national parliament to remain in power.
But it also wants to press ahead with reforms to ensure that the Indian economy, now the fourth largest in Asia, continues to grow at a healthy rate.
Finance Minister Palaniappan Chidambaram said he thought the financial impact of the strike on the economy would be "marginal".
Domestic flights were particularly badly hit, with thousands of travellers stranded.
The Airports Authority of India (AAI) said international flights operated normally. The government drafted in 3,000 air force personnel in an attempt to avert major disruption.
Unions say the strike affected services in most of India's 78 airports.
"The strike is a 100% success," MK Ghosal, general secretary of the Airports Authority of India Employees Union, told Reuters news agency.
Airports are particularly affected as many employees oppose government plans to sell 74% stakes in the Delhi and Mumbai hubs.
The eastern city of Calcutta, home to a 28-year-old Communist government, was worst hit by the strike.
The BBC's Subir Bhaumik in Calcutta says operations at the city airport ground to a halt and public transport, including the city's undeground railway, did not operate.
Cargo handling at Calcutta's port also stalled after workers there joined the strike.
Government and private offices, including info-tech companies, remained closed. Schools and colleges were also shut.
The privatisation of well-run government companies serves only the politicians and their cronies
The strike also had a major impact in the southern state of Kerala, another left-wing stronghold.
In the capital, Delhi, riot police were deployed at airport terminals.
"The morning roster staff have all reported for duty," an airports spokesman said.
But reports said there were fewer passengers than normal.
The BBC's Monica Chadha in Mumbai says more than five million federal and state government employees in western Maharashtra state participated in the strike.
Public transport services in Mumbai (Bombay) were not affected, but government offices and banks worked with fewer staff.
Many bank workers also stayed at home to protest against foreign investments in pension funds.
"This will be just a warning for the government," said MK Pandhe, general secretary of the Centre of Indian Trade Unions (CITU).
"Unless the government undertakes a comprehensive review of its policies, we will call for a much bigger action - we may go for longer strikes," he added.
India's communist parties have been leading protests across the country against the government's economic policies.
They oppose the government's policy of selling off some of its stake in state-owned corporations to raise funds for investment, privatisation of airports and allowing foreign investment in pension funds.
India's coalition government, led by the Congress Party, relies on four left-wing parties to maintain its majority in parliament.