The rupee`s sharp fall will boost earnings from oil and gas sales for ONGC, Cairn IndiaBSE 3.66 %, Reliance IndustriesBSE 0.42 % and Oil IndiaBSE -3.00 % as the dollar-linked price has risen about 17% in four months, but this is bad news for households as they will have to pay more for piped gas in their kitchen as well as petrol and diesel.