Heat, alcohol, drugs and dehydration can be a lethal mix. Whether one or a combination were involved in the death of a young man and the leaving in a critical condition of three others in their 20s, who attended an outdoor event at the West Kowloon Cultural District, will be determined by an autopsy and tests. But all factors are known to have been present at the Hong Kong leg of the Road to Ultra electronic music festival on Saturday. Inquiries have to be conducted and the findings examined by the organisers and authorities to ensure that lessons are learned from the tragedy.

Initial tests show that drugs were involved in the cases of the three still in hospital. Police found pills believed to be the party drug ecstasy and the tranquilliser midazolam when they combed the grounds at the venue, the district’s Nursery Park. But the festival was also held during hot weather, with the temperature reaching 34 degrees Celsius and there was limited shade. Some among the 10,000-strong crowd complained about difficulty in getting drinking water.

These were not the best conditions for a type of music that draws a young crowd intent on dancing and having a good time. Doctors have long warned of the risk of mixing alcohol and drugs, and the heat and a water shortage only adds to the dangers. That was the case in Manila in May last year, when five people aged between 18 and 33 fell unconscious during another outdoor music festival; all died hours later in hospital, some of heart attacks, which can be brought on by heatstroke or dehydration. That should have alerted those involved in the Road to Ultra festival, an international event established in the United States 18 years ago that traverses the globe each year.