This has been a very hot summer for many in Hong Kong, and even hotter for taxi and minibus drivers.
Under the idling bill, these drivers are required to shut down their engines when idle for more than three minutes.
To protest against the bill, about 30 taxis and minibuses drove slowly from Sham Shui Po to the Environmental Protection Department's headquarters in Wan Chai last week.
Their request for a ban on the shutdowns on very hot days has been backed by lawmakers and key green groups, after an 81-year-old minibus driver died recently inside the cabin with the engine turned off.
'If there is a clear-cut criteria [for us to enforce the law], we are happy to bring it up for Legco's discussion,' says Secretary for the Environment Edward Yau Tang-wah.