Singapore's Ministry of Manpower says employers should adjust outdoor work according to hourly PM2.5 readings. As fine-particle pollution rises during the day, outdoor work should be reduced step by step. Employers are expected to use current air-quality data when planning shifts and tasks. Workplaces may need to reschedule strenuous activity and move crews indoors as readings worsen. The guidance gives employers a graduated way to respond to pollution through the working day. It is framed as advice based on measured conditions rather than a single fixed cut-off.