Indian flag carrier Air India once again plunged into chaos Tuesday as it cancelled at least four international flights after more than 100 pilots went on strike, citing health reasons. \"We have cancelled flights from Delhi to Chicago, Toronto and Hong Kong and one from Mumbai to Newark. About 100 pilots have so far not reported for duty,\" a spokesman for Air India said. However, domestic operations have not been hampered, the spokesman said. Meanwhile, Air India has ordered all rostered pilots to report to work by 18:00 this evening or face action even as 200 more have threatened to join the strike arising out of the rescheduling of the Boeing 787 dreamliners training programme as well as over the time-bound promotion. India\'s Civil Aviation Minister Ajit Singh has reacted strongly to the strike, terming it as \"illegal\". \"They are free to come forward with their grievances but they can\'t just call in sick. The money that the government gives to Air India depends on performances; there\'s a time period involved. They can come forward for talks but can\'t put the passengers in distress,\" the minister said. The strike came a month after the Indian government had cleared a massive bail-out package for the cash-strapped state-owned carrier. In March this year, a major chunk of Air India\'s over 28,000 employees had threated to go on strike from April 2 over non- payment of salaries and dues. The proposed strike was called off after the national carrier promised to clear all salaries and other dues by June.