Prime Minister Prayut Chan-o-cha led a 5.4-kilometre anti-pollution walk along the banks of the Prem Prachakorn Canal to Wat Benjamabophit on Saturday.
Prayut chaired a ceremony to start the "People Loving Canal - No Littering, No Pouring and Doing Good" campaign at Government House at 7am.
The event was joined by about 5,000 people, including some Cabinet members, and presidents of constitutional organisations, armed forces' commanders-in-chief, senior government officials, and students from various universities as well as representatives from various communities on Bangkok canal's banks.
Speaking during the ceremony, Prayut said the walk was aimed at increasing people's awareness to preserve the environment of canals nationwide in line with the wish of His Majesty the late King Bhumibol Adulyadel.
The campaign was also aimed at doing good merit on the occasion of King Bhumibol's birthday on December 5, Prayut said.
During the event, residents on the canal banks were told not to litter or pour waste water into the canal.
As part of activities, officials measured the water quality of the canal, collected garbage and trimmed trees along the canal banks.