Over the centuries, people have sent “krathongs” – small baskets made from plants and loaded with flowers, candles, and bamboo – down waterways to make wishes and pay their respects to water spirits.

The beautiful “floating basket” or Loy Krathong festival lights up Bangkok’s canals and rivers at night – but often leaves organisers scrabbling to clear canals clogged up with hundreds of thousands of soggy vessels the next morning.

This year, participants did their best to cut down on the clean-up by drawing about 3,000 pictures of “krathongs” and scanning them into computers during the festivities.

The designs were then projected onto a colourful representation of the water’s surface.

“It really helps a lot, because it reduces cutting trees. When you float the real baskets, things fall into the water. This will help reduce waste,” said 11-year-old Jirayada Surapant, showing off her design by a Bangkok canal yesterday evening.

There was still a lot to do this morning.

Across the capital, monks set out in rowboats to scoop up the physical “krathongs” and recycle them into animal feed.

“The trash will end up in the sea, at the river mouths, completely filling them,” venerable monk Mathee Vatchara Prachatorn said, perched on the side of a boat.

“To reduce trash, everybody has to pitch in, all the villages have to help.”