On Saturday night, a football match in Indonesia exploded into violence and a stampede, killing over 170 people and injuring 180 more.

What happened in the Kanjuruhan stadium in Malang, East Java, that resulted in such a large number of deaths?

Football is popular in Indonesia, and emotions run high before large games, frequently ending in fan fights. Overcrowding and the panic caused by the police’s deployment of tear gas exacerbated the situation in Malang.

On Saturday, Arema FC hosted archrival Persebaya Surabaya at their home ground. To prevent unrest by fans of both clubs, only Arema fans were permitted inside.

Thousands of enraged fans stormed onto the ground after Persebaya triumphed 3-2, hurling bottles and other items at players and officials. According to the Associated Press, the disturbance proceeded outside, with individuals toppling and smashing police cars.

The cops then used tear gas, causing fear and a rush for the exits. The stadium had sold 42,000 tickets out of its 38,000 capacity. A five-year-old boy and two police officers were among those killed in the stampede and asphyxia. Many of the injured are said to be in critical condition.

The BBC quoted Nico Afinta, police chief in East Java, as saying, “It had gotten anarchic. They started attacking officers, they damaged cars. We would like to convey that… not all of them were anarchic. Only about 3,000 who entered the pitch.”

The use of any type of crowd control gas or rifle is prohibited under FIFA’s safety regulations. East Java police, according to Reuters, “did not immediately react to a request for comment on whether they were aware of such restrictions.”

According to Reuters, FIFA has requested a report on the incident from Indonesia’s PSSI football association, and a PSSI team has been dispatched to Malang to investigate.

The government will provide financial help to the Malang victims.

Indonesian President Joko Widodo has ordered a probe into the case. He has also ordered the premier soccer league to be suspended until a reexamination of safety preparedness.

Indonesian sports and youth minister, Zainudin Amali, said, “We will thoroughly evaluate the organisation of the match and the attendance of supporters. Will we return to banning supporters from attending the matches? That is what we will discuss.”

Indonesia’s football body has banned Arema from hosting matches for the rest of the season.