The Supreme Court today sought the reply of the Centre and Tamil Nadu Government on a petition alleging that the environmental impact of the Rs 2,400-crore Sethusamudram shipping project had not been properly studied before it was cleared for implementation. The bench headed by Justice Y.K. Sabharwal was hearing a petition filed by NGO Coastal Action Network which argued that no ‘‘comprehensive impact assessment had been made’’.The entire area, which had 54 villages, is prone to tsunami and no tsunami impact has been assessed, the NGO claimed. Reading from the initial report prepared by the environment impact assessment agency, its counsel said even the agency had admitted that a ‘‘comprehensive report will be prepared later’’.The contention was opposed by the Centre, which stated that all aspects of the project had been looked into and every environmental concern addressed.The court, however, refused to stay the dredging operations that are already under way but said it will hear all the arguments before taking a decision.Justice Sabharwal initially told the petitioners that the proper forum to address their concern was the National Environment Appellate Authority, but soon conveyed his displeasure to the Centre for not having put in place a chairperson for the authority.Coming to the Centre’s defence, Solicitor General G E Vahanvati said the issue would be resolved soon.The petitioner NGO has challenged the decision of the Madras High Court dismissing its plea opposing the proposal to build the canal through the Gulf of Mannar and the Palk Straits between India and Sri Lanka so as to provide a shorter route ships passing around India without going around Sri Lanka. It alleged that benefits from the project have been grossly exaggerated and he project was being pushed through in violation of domestic law and binding commitments to international treaties and conventions.