The drowning of three students in the basement of an exam coaching centre in India’s capital Delhi has sparked anger and protests.

The students, all in their 20s, died on Saturday night after getting trapped in the flooded basement where they were studying.

Police have arrested seven people, including the owner of the institute, and registered cases against them for causing death by negligence.

The Institute, Rau’s IAS Study Circle, is one among several in the capital where thousand of students enrol to prepare for tough national exams.

The three victims – Shreya Yadav, Tanya Soni and Nivin Dalwin – were studying for India’s Union Public Service Commission (UPSC) exams, which decide who becomes a civil servant, a much-coveted government job in India.

But many of these institutes, which are run out of cramped buildings in residential neighbourhoods, are accused of routinely flouting safety norms.

Since Saturday, authorities in Delhi have sealed about a dozen coaching centres in the area for holding classes illegally in their basements.

The Incident has also triggered a political row between the Delhi government and federal authorities, with both sides accusing the other of negligence.

Delhi is a federally-administered territory and the Aam Aadmi Party (AAP)-run local government does not have full administrative powers.

Hundreds of students have held protests around the area, accusing the administration of not doing its duty and ignoring complaints.

The tragedy unfolded on Saturday evening, after the capital had received heavy rains through the day.

Delhi’s fire department received a call around 19:00 local time (14:30 GMT) about water entering the basement of the coaching centre in Old Rajinder Nagar.

The Institute operated a library and reading room in the basement – illegally, government officials later said – and around three dozen students and some staff members were inside at the time.

Some students have told media that a gate at the entrance of the coaching centre collapsed, causing water accumulated on the road to rush in. But other reports said that a nearby drain burst due to heavy rains, resulting in a deluge.

Witnesses said the basement flooded quickly, giving people little time to escape. While some managed to do so, others had to be rescued by the authorities.

It Isn’t clear what caused the three students to get trapped inside the basement.

A student named Rajan (who used only one name) told BBC Hindi that days before the incident, the doors of the basement library had been replaced with ones that had a biometric system.

“It seems that due to water-logging, the biometric system failed and people could not get out,” he alleged.

Officials from the institute have not addressed this allegation. In a statement, Rau’s IAS Study Circle said it was “deeply saddened” by the deaths and was “co-operating fully” with the investigation.

The bodies of the three students were recovered by divers who searched the basement for several hours.

Authorities said the coaching centre only had permission to use the basement as a storeroom and for parking, and that the library was run illegally.

They also said that drains in the area had been clogged by silt, which caused water to overflow on the road.

On Sunday, several students studying for the UPSC exam – held protests demanding that strict action be taken against those responsible for Saturday’s tragedy. They also criticised poor infrastructure in the capital.

Vikram (who gave only one name) told BBC Hindi that aspirants paid hundreds of thousands of rupees in coaching fees and rent.

“But what are you giving us? Death,” he said.

Several others recalled an incident last year when a fire broke out at a UPSC coaching centre in Mukherjee Nagar in Delhi. Videos showed students smashing windows and rappelling down the building using wires and ropes. Many students sustained burn injuries.

Saturday’s incident has sparked a row between Delhi’s governing Aam Aadmi Party (AAP) and the Bharatiya Janata Party (BJP)-led federal government.

The BJP has blamed the AAP for not carrying out de-silting of drains and for the poor condition of roads. The AAP has accused Delhi’s lieutenant governor – who is appointed by the federal government – for not taking action against erring officials and claimed that bureaucrats are not following orders from ministers.

AAP leader and Delhi Chief Minister Arvind Kejriwal was arrested in March on corruption allegations that he has denied – he was released for three weeks during the general election to campaign for his party but has otherwise remained in jail.

The incident was also discussed in parliament on Monday, with opposition lawmakers asking the federal government what steps it was taking to ensure that the perpetrators would be brought to justice. The BJP lawmakers criticised Delhi’s AAP government in parliament and called for action against them for neglecting their duties towards the city residents.

Congress MP Shashi Tharoor flagged “widespread violations of building codes, fire safety and flood safety regulations” in Delhi. (BBC: Text, Excluding Headline)