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Who is this impacting?


Most polluted transportation system in the world


Above the world health organisation's recommended safe limit to PM2.5


People using the London underground every day


The average amount of minutes commuters spend on the tube daily

Tanya Beri.jpg


My name is Tanya Beri and I am the founder for CAIR London - a mobile app coming to the city to help London Underground users reduce their air pollution exposure. 

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As a born and raised Londoner, the London Underground has been a key method of transport throughout my life. Whilst it’s without a doubt one of the best transportation systems in the world, I discovered that using it was exposing us to PM2.5 (air pollution) up to 7x above the World Health Organization’s  recommended safe limit. During a ‘designing for behaviour change’ project during my masters in User Experience design, I went off to research air pollution issues in the UK and was shocked to discover how polluted the London Underground was. The tube is the most environmentally friendly and cost efficient way to travel around the city, however it’s not safe for the people using it. CAIR London is raising awareness of the tube’s current air pollution problem and provides a mobile app to generate lower polluted routes for users to travel on, creating a safer journey and a healthier experience.

When I was 18, I had a recurring case of tonsillitis which went on for 3 years until I eventually had to have surgery to remove them. When my doctors and I explored what was the sudden cause of this, the only difference there was to my day to day routine was travelling on the deeper London Underground lines which I now know are severely polluted. I may not be able to say with certainty that this was the cause of my recurring illness, but I know that there are Londoners out there with conditions such as asthma who should be aware of the problem and have a choice in how they travel so it has less of an impact on their health.

CAIR London was an award winning idea in 2020, but the moment that pushed me to turn this into a business was in 2021 when my dad took his last breath on a ventilator after going into hospital with an underlying illness and then  catching covid. We all experienced the detrimental impacts of a lung-based virus and how our health needed to become a priority, but after seeing people struggling to breathe on a covid ward it became much more personal to me. Nobody should have to struggle to breathe as a consequence of something out of their control. Travelling to work or using the tube to visit family or meet friends in Central London should not come at the cost of our health - and what’s worse is that nobody seems to be aware of the problem.


1 million people travel on the London Underground every single day and are being exposed to high levels of air pollution.


Why is the tube so polluted?

It’s a combination of many factors. We have one of the oldest underground systems in the world, dating back to 1863 when the Metropolitan Line first rode the rails. Until very recently the model of trains in use has been old, and even newer trains aren’t strong enough to withstand the pollution. There is friction in the brake mechanisms caused by the carriage moving along the rails, the brake blocks rubbing on the wheels, and the electrical connection between the collector plate and the live rail. There is a lack of ventilation across the London Underground. How deep the station is below ground, with the Victoria Line being the deepest, affects air quality. Lastly, probably the most disgusting factor is us, the passengers!

What is being done to resolve this?

TfL spends around £60 million per annum cleaning its trains, stations, and tunnels to ensure dust and particles are kept to an absolute minimum. New cleaning methods are currently being trialled and the most effective will be incorporated into TfL’s cleaning regime. 

The following information is taken directly from their website as a response to a forum question ‘What are you doing about the air pollution on the London Underground?’ In 2014 TfL scrapped a regime ‘cleaning train’ they had in place to reduce air pollution on the underground after finding it ineffective; they now are using industrial vacuums and magnetic wands but there isn’t anything published to show how effective it is. A similar attempted solution conducted in Toronto implementing more frequent cleaning also proved to show no change to the PM2.5 readings on the underground platforms (Ryswyk. K et el, 21).

So as it stands, there is currently no confirmed solution to this problem. Honestly, TfL has a very difficult job right now and I’m not trying to undermine the hard work I know they are doing to try and fix this. They have been working with Imperial College London to explore their options, working with some of the leading academics who are writing papers about this problem.


Following our Founders young innovators award 2023 announcement, we've been fortunate enough to be featured in various media press releases. You can find the links to the various articles below.



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