DURING a recent visit to Hong Kong, Shanghai and Taiwan, I noticed that supermarkets and convenience stores made shoppers pay for plastic bags. Singapore has its own 'Bring your own bag day', but it is hardly enforced. I urge the National Environment Agency and retailers here to beef up enforcement of this initiative. Retailers here should also impose a 50-cent charge for each plastic bag. This will encourage people to reuse, reduce and recycle plastic bags.