Public disapproval of Chief Executive Donald Tsang Yam-kuen's policy address has deepened amid the furore over light bulbs, a poll has found. Allegations have been made that Tsang intentionally favoured an in-law's light-bulb business when he launched a scheme to encourage the use of energy-saving light bulbs. The latest rating for the policy address was 49.8 points out of 100, down from 53.5 immediately after the address was delivered last Wednesday, the poll by the University of Hong Kong's public opinion programme, released yesterday showed. The rating, taken from a poll carried out between Thursday and Saturday, during the controversy, was the lowest in the past five years, during which no policy address had received a rating of less than 50 in the same series of HKU polls. Power firms are to give every home HK$100 coupons in December for them to buy fluorescent light bulbs. Fears have been voiced over a possible conflict of interest involving Tsang and his elder son's father-in-law, Anthony Mok Kam-chuen. Mok is one of the biggest distributors of compact fluorescent lamps manufactured by Philips, which has up to half the market, leading to allegations that the HK$240 million coupons scheme could favour him. Although Tsang admitted he had failed to declare the interest, close allies on the Executive Council yesterday backed him after he appeared to have convinced councillors the allegations were unfounded and that the scheme was in the public interest. Exco convenor Leung Chun-ying said: 'I, and other ex-officio councillors, don't believe the light-bulb scheme in the policy address intentionally favours any party or [that Tsang] has conflicts of interest.' A person familiar with the situation said yesterday that environment minister Edward Yau Tang-wah had appeared at the council meeting to explain how the coupon scheme was drawn up. Councillors said it had been the government's policy to promote green lighting. The person said Tsang told Exco members during the meeting that he had included the initiative in the policy address because it was in line with the goal of a low-carbon economy. However, the university poll also found only 45 per cent of respondents believed Tsang's blueprint served the needs of society, also the lowest in the past five years. The satisfaction rate for the address fell from 30 per cent to 19 per cent, while the dissatisfaction rate rose from 28 per cent to 31 per cent. Dr Ma Ngok, associate professor of government and public administration at Chinese University, said public perception towards the policy address might have been influenced by many factors, but media reports on the controversy would have had a direct impact on the ratings. The university poll carried a margin of error of plus or minus three per cent.