Air passengers found themselves stranded in several places, schools were shut and financial services hit across India Thursday as millions struck work to protest the government's free market reforms.

A daylong strike by some 20,000 workers of the state-run Airports Authority of India (AAI), which manages 124 airports in the country, badly affected domestic and international aviation services in Asia's third largest economy as left-backed trade unions agitated.

Flights were disrupted in places like Mumbai, Delhi and the northeast as airport workers protested the privatisation of Delhi and Mumbai airports.

Kolkata appeared to be the worst off. No flight could either take off or arrive at the Netaji Subhas Chandra Bose International airport, though an Indian Airlines flight from Delhi arrived at the airport at 10.15 a.m.

"The strike is a complete success," Nitin Jadhav, joint secretary of the Airports Authority of India Employees Union, said in Mumbai.

"Despite the government's attempt to seek outside help to maintain normal operations, all services have been badly affected," Jadhav told reporters here.

Long queues of passengers were seen at the domestic airport of the country's financial capital to cancel their tickets.

Airlines like Jet Airways, Air Sahara and Indian Airlines cancelled many of their flight services to and from Mumbai. In Delhi, Air Deccan cancelled its flight to Amritsar and Kolkata.

Jet Airways and Air Sahara also cancelled all their flights to and from Kolkata and many other eastern Indian cities. Kingfisher Airlines curtailed daily services by 25 percent.

In places like Bangalore and Lucknow, however, airport activities did not suffer much.

Financial services across the country were hit as nearly one million public sector bank employees went on a nationwide strike to protest the proposals to privatise state-run banks.

The strike crippled all banking transactions, including clearance of cheques across the country.

"The response to the strike is better than what we had expected. We have got very encouraging reports from all over the country," Peter Fernandez, secretary of the All India Bank Officers' Confederation (AIBOC), said in Mumbai.

Eight other bank employees' unions, including All India Bank Employees' Association, National Confederation of Bank Employees, and Bank Employees' Federation of India supported the strike call.

Roads were deserted as schools, shops and other establishments remained shut in many parts of the country like Kerala and West Bengal. Transport unions, including state-owned services, took part in the protest. Train services were also hit in many places.

The Congress-backed Indian National Trade Union Congress and the Bharatiya Janata Party's Bharatiya Mazdoor Sangh did not participate in the agitation.

In most parts of the northeast, police and witnesses said roads were deserted, with both public and private transport not plying. Trains and air services in the region too were hit.

In Assam, normal life was paralysed following a 12-hour general strike called by the People's Committee for Peace Initiative Thursday to protest the central government's delay in initiating peace talks with the outlawed United Liberation Front of Asom (ULFA).

Though most parts of the country remained peaceful, there were reports of violence from New Delhi's industrial suburb of Gurgaon where workers' unions tried to force closure of factories.

Activists of various unions clashed with the police at several places in the industrial town. Windowpanes of industrial units were smashed at several places.

Some reports suggested that nearly 200,000 workers could not reach their workplaces in the morning as striking unions had blocked roads.