In what is seen as an effort to calm the streets in Kerala,Prime Minister Manmohan Singh on Wednesday sought a conducive atmosphere as a virtual pre-condition for Central intervention in the row over Mullaperiyar dam. Concerned over escalation of tension,particularly along the Kerala-Tamil Nadu border,Singh urged an all-party delegation,led by Chief Minister Oommen Chandy and Leader of Opposition V S Achuthanandan,to ensure normalcy was restored at the earliest. The delegation had called on him to seek his intervention in the issue. Heeding the Prime Ministers advice,Chandy appealed to protesters to vacate the streets. State Congress president Ramesh Chennithala,who was part of the delegation,said the Congress would call off its agitation. Kerala Congress (M) leader K M Mani,whose party is at the forefront of the agitation,too said he would respect the advise. Sinking their differences,the Congress,CPM,BJP,and a host of local parties in Kerala have joined forces to demand a new dam at Mullaperiyar. In fact,on Wednesday,Chandy and Achuthanandan left in the same car after meeting the Prime Minister. In a memorandum to the PM,the delegation said that continued unprecedented seismic activity in the region and rise in water levels in the reservoir have intensified the possibilities of imminent danger and have raised fear and panic among the people. Though they stressed that a new dam was the only lasting solution to the row,they urged Singh to persuade Tamil Nadu to come to the table with an open mind. The Centre,they added,should mediate in such talks. Chandy later said Singh had agreed to intervene despite certain limitations. He also asked the two states to create a congenial atmosphere for talks,he said.