New Delhi, Apr 16 (PTI) The government has cut the supply of lower-cost APM gas to city gas distributors such as Indraprastha Gas Ltd, Mahanagar Gas Ltd, and Adani Total Gas Ltd, by up to 20 per cent, replacing the shortfall with more expensive fuel. GAIL (India) Ltd, the state-owned nodal agency for gas supply, has intimated about a cut in supply of gas from legacy fields, called Administered Price Mechanism (APM) gas, the three city retailers said in separate stock exchange filings. The production of APM gas, which is currently priced at USD 6.75 per million British thermal unit, is declining at the rate of 9-10 per cent annually as recovery from old and ageing fields falls.