Air pollution continues to choke Hong Kong's appeal among expatriates as a place to live and work in, although improvements in transport and communications helped the city climb the global rankings to number 8 in an annual survey. The findings, compiled by human resources consultancy ECA International, show that Hong Kong has managed to narrow the gap globally with top-ranked Singapore this year. 'Air pollution in Hong Kong continues to be the dominant factor that makes Hong Kong a harder location for international assignees to adapt to living in,' Lee Quane, ECA's regional director for Asia, said. The annual survey ranked 254 cities in terms of their quality of life. The data is designed to be used by companies to determine whether they need to pay hardship allowances for relocating expatriate employees. Hong Kong is routinely named among the top, if not the top, market in the world for its economic exploits. But air pollution has long been blamed for hurting the city's attractiveness. Just this week, Hong Kong was affected by the strongest sandstorm to hit the mainland this year, sending its air pollution index off the charts. The survey found Hong Kong, along with Beijing and New Delhi, among the worst locations in terms of air quality. A spokesman for the Environment Bureau said efforts to tackle air pollution were continuing locally and in co-operation with Guangdong authorities. He said that between 1997 and 2008, emissions of smog components, like sulphur dioxide, nitrogen oxides, respirable suspended particulates and volatile organic compounds, had fallen by 13 per cent, 29 per cent, 54 per cent and 50 per cent, respectively. Singapore remained in first place globally, followed by Sydney, Kobe, Yokohama, Tokyo, Copenhagen and Canberra. Hong Kong was ranked No 8 while Melbourne and Dublin rounded out the top 10. Shanghai was the highest ranked mainland city at No 77.