NEW DELHI - Singapore state investor Temasek, the majority shareholder of Singapore Airlines, on Saturday backed the airline's investment in Air India, as scrutiny grows over its stake in the loss-making Indian carrier.Air India's request for about US$1.5 billion (S$1.9 billion) in fresh equity from owners Tata Sons and Singapore Airlines was first reported by Reuters this week. Singapore Airlines owns 25.1 per cent of India's second-largest airline, with the rest owned by Tata.News of the funding request prompted Kenneth Tiong, a lawmaker from Singapore's opposition Workers' Party, to urge that Temasek's funds not to be used to shore up the Indian carrier.Singapore's Business Times also ran a commentary arguing that Singapore Airlines could not realistically exit its Air India stake, with Tata the only plausible buyer. It questioned what its 25.1 per cent holding offered beyond a board seat and a share of the losses, while saying the strategic logic of the investment still held. Read more