At National Commodity and Derivatives Exchange, refined soya oil for delivery in October declined by Rs 1.75, or 0.27 per cent, to Rs 638.50 per 10 kg, with an open interest of 7,345 lots.
Similarly, the oil for delivery in November traded lower by Rs 1.45, or 0.23 per cent, to Rs 634.85 per 10 kg in 77,365 lots.
Market analysts said apart from slackened demand in the spot market, adequate stocks position on higher supplies from growing regions, mainly influenced refined soya oil prices at futures trade.