SINGAPORE - Despite the light rain in the morning, an estimated 10,000 people headed outdoors on Sunday to join in Singapore's first national litter-picking exercise.

They converged at about 130 locations, armed themselves with gloves, trash bags and tongs, and then fanned out again to pick up cigarette butts, plastic bags, tissue paper and, in some cases, even discarded cardboard packaging.

The volunteers were part of Operation We Clean Up!, a one-day event organised by the Public Hygiene Council, Singapore Kindness Movement and Keep Singapore Beautiful Movement to rally people to clean up after themselves and others.

More than 8,000 people are expected to join in the national effort, which will last until Sunday evening. In Bukit Panjang, the people who showed up in the morning included father-and-daughter team Kevin and Kezel Ong.

Kezel, 7, told The Straits Times that she was sick of seeing cigarette butts and other rubbish in her estate. "Our playground and void deck can get quite dirty, and it makes our neighbourhood look ugly," she said.

To show people how much rubbish can be littered in a single day, general area cleaning was stopped in nearly 70 precincts on Saturday and the cleaners given a rest day. Almost 5,000 cleaners across the 15 PAP town councils were also treated to an appreciation lunch on Sunday, and given a $20 NTUC FairPrice voucher each.

Mr Tan Hock Chye, 54, one of the cleaners, said he appreciated the acknowledgement of their work. He said: "It's good for encouragement and morale, but it would be even better if more people would learn not to litter everywhere, and throw their rubbish away properly too."