Hong Kong may style itself as Asia's 'world city' but the continent's expatriates do not rate it among the world's top 10 places to live. Expatriates from Asian countries regard Singapore as the world's most desirable location, followed by Sydney and Melbourne, and put Hong Kong in 15th place behind Yokohama and on a par with Tokyo. The findings were announced in a survey by recruitment consultancy ECA International. The consultancy ranks 254 cities worldwide for the quality of life they offer to Asian expatriates across 15 sectors in the annual survey, including transport, recreation facilities, housing, health care, housing, crime and air quality. It said Hong Kong had risen from 23rd position last year because the crime rate had improved, but air pollution had worsened. General manager Lee Quane said: 'Air pollution is the main reason why Hong Kong comes 15th in comparison to Singapore. In all the other factors - including the quality of health-care facilities, recreational facilities and infrastructure - Hong Kong and Singapore score quite similarly. 'I have seen from personal experience that many expatriates have indicated their preference to live in another Asian city such as Singapore due to Hong Kong's relatively poor air quality,' he said. Mr Quane said the survey was used by multinationals to decide whether they should pay a hardship allowance to employees who were moved to another country. The further down the ranking a country was, the more likely the company was to pay the allowance. Levina Poon, an associate director with international headhunters Robert Walters, said air pollution was a factor that expatriates considered when deciding whether to accept a job offer in Hong Kong.