Prime Minister Prayut Chan-o-cha has ordered authorities to strictly enforce a ban on boats dropping anchor, causing damage to coral reefs.
Deputy government spokesman Sansern Kaewkamnerd said many boats are shuttling Songkran revellers to offshore islands which are home to rich marine wildlife and coral reefs.
The authorities have designated buoy areas close to shore for boats to moor. However, some boats drop anchor, causing damage to undersea coral.
Maj Gen Sansern said the prime minister was worried about the fate of the coral and had ordered the Marine Department and marine police to enforce the anchor ban and patrol offshore tourist attractions, particularly those in the Andaman Sea. "The corals are natural treasures which must be preserved for the sake of the tourism industry," he said.
As ordered by the National Council for Peace and Order (NCPO), the reported holiday road toll has fallen compared with last year.
Meanwhile, the National Institute for Emergency Medicine says motorists playing on smartphones and dozing off behind the wheel are two big causes of road accidents.
Some drivers feel sleepy, slowing their responses to traffic situations, said Anuchar Sethasathien, the institute secretary-general, who said they should pull over in a safe place and take a rest.
The Department of Land Transport (DLT) said 1,550 motorists were caught speeding between Thursday and Sunday.
Theerapong Rodprasert, the DLT director-general, said drivers of 1,550 public transport and freight vehicles were caught speeding, 515 were public vans, and the rest large buses and trucks. Errant drivers are fined up to 5,000 baht and can lose their licences.
In the past four days, the department has found 192 public transport vehicles have problems, mostly with faulty windscreens, side mirrors and lights. A total of 128 drivers were found unfit to be driving and fined. Many had driven non-stop for more than the four-hour legal limit.
In Ayutthaya, about 100 angry youths and street vendors protested against provincial authorities for prohibiting them from holding a live concert and foam party on U-Thong Road for Songkran.
The group marched along the road towards the provincial hall to submit a letter of protest to governor Apichat Todilokvech.
Authorities had ordered residents to pull down a concert stage at the mouth of Soi Bua Warn on U-Thong Road. Police said the ban was ordered by the National Council for Peace and Order, which has urged the public to celebrate Songkran in an orderly manner.
The protesters dispersed after police negotiated with them for an hour at the provincial hall. They agreed vendors could still sell food and drinks and the organiser could play music on speakers to entertain Songkran revellers.
Silom Road is filled with revellers turning up for the Songkran water splashing fun. A section of the commercial road is closed for the celebrations. Chanat Katanyu
Young women come fully prepared with goggles and water guns as they brace for a splash outside the CentralWorld shopping complex. Chanat Katanyu
A woman fights off her opponents in a water fight on Khao San Road, a popular city spot for the Songkran festival. Narupon Hinshiranan
Water spills in all directions as people pour out onto the streets to join the Songkran celebrations on Koh Samui. Thanarak Khunton
Revellers engage in a water fight on Koh Samui, one of the country's favourite playgrounds for the Songkran celebrations. Thanarak Khunton