KARACHI - Pakistan State Oil (PSO) has suspended oil supply to PIA on account of non-payment of outstanding dues. PIA sources said PIA has to pay outstanding dues of over Rs 16 billion to PSO and the former is facing difficulties in clearing these dues due to financial crisis.  PSO agreed on receiving dues from PIA on monthly basis due to government functionaries’ mediation but PIA has failed to make payment on monthly basis as well. PIA flights from Karachi to Lahore and Islamabad have been affected badly due to suspension of oil supply by PSO.