HONG KONG breathed easier last month as pollution fell well below the record levels of March, the latest figures show. The Air Pollution Index stayed under the 100 level - at which people with breathing problems are advised to stay indoors - for all of April. This was in sharp contrast to the situation just weeks before. In March, the SAR recorded its highest level of roadside pollution, and the index topped 100 on six days. Readings at roadside stations last month ranged from 64 to 99, with the worst measure taken on April 14. Levels at general stations fluctuated between 42 and 84. The Environmental Protection Department did not respond to requests for an explanation yesterday, but it is thought the heavy downpours of recent weeks may have played a part in bringing down pollution levels. Almost 41mm of rain fell in March, compared with nearly 548mm in April, according to the Hong Kong Observatory. And there were just 77 hours of sunshine, compared with almost twice that - 137 hours - in March. The usual amount of sunshine for this time of year is about 109 hours a month. High air pollution figures are sometimes attributed to warm, sunny and still weather, which allows particles to remain suspended in the air. Hong Kong's record-high pollution reading came on March 29 in Central, when 174 was registered at the roadside testing station. Forty-six convictions for pollution offences were recorded last month, most for breaching rules on the creation of dust at building sites. After a tree-planting session in South Lantau Country Park yesterday, CLP Power, formerly China Light & Power, said it had reduced carbon-dioxide emissions by 29 per cent over the past 10 years. Chairman William Mocatta said the reduction, achieved by replacing some coal with natural gas in the production process, came despite a 50 per cent rise in electricity demand in that time.