Air India’s Clogged Toilets: Passengers May Not Be To Blame Entirely

India’s flag carrier Air India made headlines last week for all the wrong reasons, yet again. This time it was clogged toilets on the plane that forced Air India Flight 126, en route from Chicago to Delhi, to return to Chicago O'Hare International Airport after its toilets were found to be clogged mid-flight.

Amid varied reactions on social media, Air India said that its teams found “polythene bags, rags and clothes” had been flushed down the toilets. “This led the lavatories to become unserviceable,” Air India said in a statement after the incident.

Eight out of the 12 lavatories on the flight had reportedly been impacted and the decision to return to Chicago was taken since potential diversion points in Europe were under night-time operational restrictions.

“When a tank gets blocked because the line or the tank inlet is blocked, you lose 4 lavatories at a time. In this case, the Air India flight lost 8 lavatories because 2 tanks were blocked. And it wouldn't be advisable to continue on an ultralong flight with more than 50% of your lavatories blocked,” an aircraft maintenance engineer with a middle-eastern airline told The Core on condition of anonymity.

While the airline in its statement urged “passengers to use lavatories only for the purposes that they are meant for”, aviation experts The Core spoke to highlighted the failure to keep up maintenance. Maintenance issues have plagued Air India as it tries to revamp its image and services.

How Do Aircraft Lavatories Work?

Close on the heels of the incident, social media was flooded with images and videos of an aircraft maintenance engineer cleaning plumbing pipes, with soiled clothes reportedly discovered in the system.

“First of all, this whole thing is absurd. The pictures circulating — blankets and plastic packets clogging the toilets — that’s pure nonsense. Those are old photos being pushed by an aviation expert, not evidence of what happened,” Mark Martin, founder and CEO of aviation consultancy Martin Consulting, told The Core.

Modern aircraft lavatories operate using a vacuum-based system that removes waste through suction rather than relying on gravity. The system is designed to prevent clogs, but objects such as clothing, towels or plastic items can disrupt its functionality.

The plumbing lines for aircraft lavatories are flushed with a chemical solvent and dry ice every 14 days to keep the system clear, while the tanks are drained and cleaned before each flight.

“Usually for a B777, the only time we open everything is when we get blocks like this or during heavy maintenance routine,” the engineer quoted above explained.

When the flight had to return, Air India first commented saying that this happened because women had flushed sanitary napkins in the toilets.

“Let’s be clear—nine out of ten toilets on a plane don’t all fail at the same time. That’s just not how aircraft plumbing works. What’s even worse is the claim that women flushing sanitary pads caused this. Seriously? That’s not only ridiculous but also insulting to women’s intelligence,” Martin said.

Aircraft have to undergo deep cleaning before every takeoff, but each airline follows its maintenance schedule. These schedules are determined by the operator and outlined in a document called the maintenance planning document (MPD), which aircraft manufacturers provide as a guideline for routine servicing.

“An operator can choose to make its own maintenance cycle as per cost and time, but within the time frame mentioned by manufacturers,” said the engineer.

Recurring Issue: Not the First Time

This is not the first time an Air India flight has faced such an incident. In March 2017, a Boeing 777 flying from Delhi to Chicago departed with 4 lavatories already clogged. As the 16-hour journey progressed, the remaining 8 lavatories also became inoperative due to passengers flushing items like plastic bottles and sanitary napkins. The situation led to severe discomfort for passengers and crew alike.

In 2016, an Air India flight from Newark to Mumbai had to divert to Istanbul due to a malfunction in the flushing mechanism of all onboard toilets. Approximately five hours away from Mumbai, the crew noticed that none of the toilets were functioning, leading to the unscheduled landing for repairs.

Martin believes that this issue was not a passenger's fault but the failure of maintenance by the airline.

“Aircraft lavatory tanks aren’t one giant system; they’re divided into multiple tanks—aft (rear), centre, forward. If one tank gets clogged, the others should still work. So blaming one supposed blockage for taking down multiple lavatories just doesn’t add up,” he added.

But why did Air India return back to Chicago instead of making an emergency landing?

“They could’ve landed in Dublin, London, or Glasgow. Simple: if they landed in Europe, the real issue would have been exposed. Ground crews would’ve inspected the aircraft and called them out on their failure,” Martin said.

Air India acknowledged that similar issues have occurred on other flights in the past.

“While not found on AI126 of March 5, 2025, our teams have previously also found objects such as blankets, innerwear, and diapers, among other waste, having been flushed down the lavatories on other flights,” the airline's statement added.

Why Does This Keep Happening?

Engineers suggest that passenger behaviour and lack of awareness contribute significantly to these problems. Air India provides pyjamas and blankets on its long-haul flights, unlike on its shorter routes.

Many passengers tend to carry these amenities into lavatories, and sometimes, they end up in the waste system, is what the aircraft maintenance engineers said.

“With Indians, I think it’s a lack of knowledge and etiquette, I suppose. A cultural thing or an Indian norm. I guess we don’t keep waste bins in our toilets at home, so that is the reason,” said the engineer who works with a Gulf carrier.

Once an item falls into the lavatory, retrieving it becomes unlikely. Instead, many travellers attempt to flush it away, assuming the vacuum suction will take care of it. However, the reality is different.

“When something falls into the toilet while people are… well, doing their business, they don’t always make an effort to retrieve it. The polite thing would be to pick it up and dispose of it properly, right? But that rarely happens,” said another aircraft maintenance engineer from an Indian airline.

Martin however disagreed with the general consensus and was of the opinion that the lavatories just hadn’t been cleaned or maintained properly. “Claiming someone stuffed a pyjama down the toilet? That’s just insulting to every Indian passenger on board," Martin said.

What Ends Up in Airplane Lavatories?

Besides clothes and rags, passengers have been known to flush items such as face towels, baby diapers, sanitary napkins, tissue paper, and even toiletry bottles. Over time, these accumulate and lead to serious blockages.

Paper cups are another surprising culprit.

“During my time with a previous airline, there were incidents where passengers didn't know how to use the flush properly. After they were done, they would often use disposable cups in the lavatory. They would pour water into the cups and think that’s how it gets flushed. Then, they would throw the cup in and press the flush button, causing a bunch of cups to get stuck in the waste line,” said the Indian airline engineer.

What’s Next for Airlines?

Incidents like these highlight the need for better passenger education regarding proper lavatory usage. Airlines may need to introduce clearer signage, in-flight announcements, or even brief instructions in multiple languages to prevent future occurrences.

Ultimately, ensuring smooth and comfortable travel experiences is a shared responsibility between airlines and passengers. A little awareness and common courtesy can go a long way in preventing such costly and inconvenient mid-air disruptions.