Shanghai formally opened its doors to outsiders yesterday, releasing details of new rules that allow them to become permanent residents. The tiered system will mean some incomers will be able to qualify for the coveted hukou in as little as three years - but for most it will take at least seven. The rules, which are being implemented on a three-year trial basis, are aimed at switching from a quota-based mechanism providing permanent residency according to profession to one based on clearly defined entitlement criteria. 'We can definitely guarantee the system is fair and just,' said Mao Dali , deputy director of the Shanghai Municipal Human Resources and Social Security Bureau. Mr Mao pledged that city officials would handle applications within 60 working days. The first hukou to be issued using the new criteria could be released within three months, Mr Mao told a press conference yesterday. Under the basic requirement - first floated by the municipal government in February - immigrants must have been formally registered as a resident of the city for at least seven years. Applicants will need a stable income, a 'good credit rating' and to have paid social security and tax in the city throughout the period. However, the city hopes the new system will boost its competitiveness in attracting talent. Professionals in certain fields and those holding top-tier national technical qualifications will be able to jump the queue. There is also a shortcut for the wealthy. Immigrants who have posted a taxable income averaging more than 1 million yuan (HK$1.14 million) for three consecutive years will not need to meet the seven-year residency requirement. Entrepreneurs employing at least 100 people in the city for three years will have the same advantage. Teachers and hygiene workers in rural districts around the city's periphery are also being given priority. They can apply after just five years' residency. According to population figures from the Shanghai Municipal Statistics Bureau, fewer than 13.6 million of the city's 18.6 million inhabitants held a local hukou at the end of 2007. But Ye Mingzhong , the deputy director of the Shanghai Municipal Development and Reform Commission, said officials did not expect to be overwhelmed with applications during the first year. 'Since the pilot system for issuing residence permits was introduced in 2002, applications have increased year on year, reaching a total of 270,000 by the end of 2008,' he said. 'But the number of successful applications in '02, '03 and '04 was not so high.' Currently there were just 3,000 residency-permit holders who had reached the seven-year requirement. The hukou system used throughout the mainland in effect ties access to public services to a person's place of birth. Shanghai's resident-permit system was initially offered to talented migrants in 2002. It was extended to all immigrants in 2004.