The health ministry is also working with Cold Storage, Giant and Sheng Siong to make N95 masks, or their equivalent, progressively available across all their outlets.

The Singapore Environment Council issued the restriction on Sunday after three of APP's wood-fibre suppliers were linked to fires in Indonesia that caused haze in Singapore. 

The additional guidance complements existing guidelines based on the 24-hour PSI forecast, said the manpower ministry.

Food delivery riders say they have not been penalised for delays during the haze, but some worry that slower deliveries could affect their earnings.  

The palm oil producer said it is confident that an objective review of the available evidence will prove that it does not engage in any land clearing by fire, whether directly or indirectly. 

Among other assets, the will bequeathed a property in Eng Kong Road to two of the sons, which was later sold for S$5 million.