By Nidhi Verma, Nupur Anand and Chris Thomas NEW DELHI/MUMBAI/BANGALORE (Reuters) – India’s HDFC Bank and some foreign banks have stopped offering trade credit for oil imports to Nayara Energy, a Russian-backed refiner, and some suppliers are seeking payment upfront to avoid potential problems resulting from western sanctions against Moscow, four banking and industry sources said. Nayara has not been sanctioned as part of the international response to Russia’s invasion of Ukraine, but Russian energy giant Rosneft, which owns 49% of the Indian refiner, has been. To avoid the need for credit to …