The director of environmental protection has quietly exercised discretionary powers to introduce a new exemption to the already much diluted ban on idling engines.
The change, approved by Anissa Wong Sean-yee on April 30, came into force on May 11 when it was gazetted without prior publicity, and adds about 200 vehicles to those able to keep their engines running in the streets.
Drivers of private light buses for an organisation carrying people who are physically or mentally disabled, and drivers of a mobile clinic providing medical consultations on board, can apply for the exemption.
The changes are the first since the ban, aimed at cutting air pollution, took effect in December, much watered-down from the original version after lobbying from the transport trade.
It drew criticism from Democratic Party lawmaker Kam Nai-wai, who said such changes should be posted on the department's website to allow public comment.
Kam urged the department to explain clearly the criteria it used to approve the exemption and how many vehicles were involved.
'The public has the right to know under what conditions an approval is likely to prevent abuse of power.'
A spokesman for the department said the director had discretion to exempt a driver or class of drivers if she was 'satisfied that exceptional circumstances exist that make it impractical or unreasonable for drivers to comply'.
But the spokesman would not say how many exemption applications Wong had received or how many were still being processed. He noted that lawmakers had supported granting exemptions on individual merit.
Drivers already enjoy a three-minute grace period and a general exemption when the weather is poor, such as during rainstorm or very hot weather warnings.
During the legislature's debate on the idling engine ban, environment officials rejected suggestions that a general exemption should be granted to people with health problems, as it might be abused and make enforcement difficult.
The spokesman said six welfare agencies had been granted the exemption: the Hong Kong Society for Rehabilitation, the Salvation Army Hoi Yu Day Care Centre for Senior Citizens, the Christian Family Service Centre, United Christian Nethersole Community Health Service, the Salvation Army Tai Po Multi-service Centre for Senior Citizens, and the Tung Wah Group of Hospitals.
'It is necessary to maintain ventilation inside the vehicle cabin with the air conditioner, as the passengers on board may not be able to properly take care of themselves, open the windows or get out of the vehicle when [it] is waiting for other passengers,' the spokesman said.
Yan Oi Tong and the Hong Kong Federation of Trade Unions Workers' Medical Clinics are also given exemptions for their mobile clinics to ensure equipment is supplied with power and to provide ventilation for waiting patients.
The spokesman said there was no legal definition of mobile clinics and an individual assessment of the merit of exempting them was needed.
A spokeswoman for the Tung Wah Group said exemptions for the 54 private light buses it operates for the elderly and disabled were necessary as 'they are vulnerable to high temperature'.
'In more serious situations, they may even run the risk of epilepsy or loss of consciousness,' Ava Ho, the groups' assistant manager of corporate communication, said.
Yan Oi Tong's spokeswoman said the organisation had 17 vehicles, including a 24-seat private bus, and a five-tonne truck.