Bon Om Touk - the Cambodian water festival, when racing boats and candle offerings fill the Tonle Sap

Bon Om Touk is Cambodia's water festival, held over three days in the twelfth lunar month to mark the moment the Mekong flood stops rising. Long racing boats, floating candle offerings and roughly a hundred thousand spectators fill the riverbanks of Phnom Penh.

The one-line summary

Three-day Cambodian water festival in the twelfth lunar month, usually November. Cultural category, iconic tier. The country's longest holiday break and its de facto new year.

Origin

The Tonle Sap reverses direction each year. For most of the dry season the Mekong draws water out of the lake; when the monsoon arrives the flow flips, the lake swells by several million tonnes of water a day, and the flood pulses back down through the delta. The older Khmer name, Bon Ok Louk, means "back water turning the current". The festival celebrates that reversal as the moment the dangerous part of the flood is over.

Theravada Buddhist practice shapes what happens in the festival. Bon, which means merit, names both the offerings floated on the water and the good deeds those offerings represent. Boats have been racing on the Tonle Sap for well over a century; the modern organised event dates to the colonial era, when the races were institutionalised as a national display.

When it falls

Three days of the twelfth lunar month, so usually November and sometimes spilling into early December. Because the dates follow the lunar calendar they are gazetted annually, and Cambodia attaches three or four public days - the longest statutory break in the national calendar, and the period when most Khmers travel home.

How it is observed

The races run on the Tonle Sap and the adjacent channels. Boats are long, narrow and low in the water, crewed by as many as 85 rowers working in time with a standing helmsman who calls the stroke. The wooden hulls last a single race, so the river fills with broken planks and paddles while the crowd watches from packed banks.

The evenings belong to bon. People assemble small offerings of banana trunk, coconut, sticky rice, sandalwood, flowers and lit candles on the water and set them drifting downstream, then follow them along the bank. Illuminated processions, floats and fireworks run late into the night.

Public status

Bon Om Touk is a Cambodian public holiday with the longest continuous break in the national calendar. Roads out of Phnom Penh are reported as gridlocked for days either side, which makes it the country's dominant domestic travel period.

Where it is contested

The festival has drawn criticism on environmental grounds. The races run over the same waters that support the Tonle Sap fishery, and Cambodian conservation groups have argued that boat density, noise and fuel use damage spawning habitat and reduce catches. Organisers have responded with smaller fuel limits and scaled-back entry fees in recent years, and the race has survived every version of that argument.

Related holidays

Bon Om Touk is the Cambodian member of a four-country family of Mekong water new years: Thailand's Songkran, Laos' Boun Lai Heua Fai and Myanmar'sThingyan. The dates differ because each country uses a different calendrical reckoning for the flood, so the four new years routinely land in three different Gregorian weeks.

Sources

• Ministry of Tourism Cambodia(festival programme, boat-race tradition and the meaning of the Tonle Sap reversal).
• UNESCO - Intangible Cultural Heritage(listing and documentation of Khmer ritual and performing-arts traditions).
• Encyclopaedia Britannica - Tonle Sap(hydrology of the annual flow reversal and the flood pulse).
• Royal Government of Cambodia(annual gazetted holiday dates).