New Delhi, Dec. 16 :    New Delhi, Dec. 16:  Getting tough with the striking postal employees, many states today invoked the Essential Services Maintenance Act (Esma) against them even as the unions reaffirmed their resolve to continue the 12-day stir till all their demands were met. An official spokesperson said Delhi, Himachal Pradesh, Haryana, Chandigarh, Uttar Pradesh, Uttaranchal, Andhra Pradesh and Gujarat have invoked the provisions of the Act. Official sources said other states were expected to follow suit. Delhi was the first state to issue the order last night after the Centre on Thursday had declared the strike illegal. According to a UNI report, staff at the New Delhi Head Post Office were back to work fearing arrests. And though the post office wore a deserted look, there were staff behind the counters attending to customers. Enacted under Chapter III of the Constitution, Esma is a stringent piece of legislation aimed at preventing the collapse of essential services under government control. The law stipulates a jail term of six months to one year for those who fail to comply with the order. The Act allows the Central government to ban strikes and requires conciliation or arbitration in specified essential industries, though legal mechanisms exist for challenging the assertion that a given dispute falls within its scope. As disruption of essential services is a non-bailable, cognisable offence, the jail term under this Act can even be extended up to three years. However, Pawan Duggal, a Supreme Court advocate, said the Act had lost its 'relevance'. 'The government only invokes it but fails to implement it. This is a major reason why striking employees do not take this Act seriously,' he said. Meanwhile, the employees' federations, which gave the strike call, are holding an emergency meeting of the Joint Council of Action to decide their course of action. According to V.S. Yadav, secretary-general of the Bharatiya Postal Employees Federation which is affiliated to the BJP's Bharatiya Mazdoor Sangh, 'the employees will continue their struggle'. 'We are open to talks and ready to work on a negotiated settlement if the government invites them to the negotiating table,' Yadav said. The government has asked all retired postal department employees, school and college students, home guards, National Cadet Corps and Non-Governmental Organisations to participate in the maintenance of postal services. Official sources said computer institutes will also be roped in to maintain VSATs or long-distance hot lines used by computer networks. 'The process will be completed by Monday. The post offices will have more than 75 to 80-percent strength and adequate measures have been taken to maintain security of postal services,' said a senior postal department official.