Former President R. Venkataraman will inaugurate a national convention of NGO's which will focus on issues like Panchayati Raj, open market policy, environment and socio-political issues."More than 300 NGO activists are likely to participate in the two-day convention starting here on September 21, to deliberate on contemporary issues facing the nation and the role of the voluntary sector," Mr Anil K. Singh of Voluntary Action Network India, organiser of the convention said.VANI, a network of 234 voluntary groups is organising the convention to launch a campaign to bring transparency and accountability in the NGO sector, Mr Singh said.