Stop, go: Hitting the roads to clean London’s air

The Great Smog of 1952 — a lethal haze of smoke and fog — killed nearly 12,000 people in London. Since then, efforts to improve air quality in the buzzing capital have come a long way, mainly due to targeted road pricing, but also by encouraging cycling and walking

By Prasun Sonwalkar

  • Follow us on
  • google-news
  • whatsapp
  • telegram

Top Stories

Published: Fri 7 Oct 2022, 10:47 PM

Certain roads, landmarks and signs become so familiar that you are lulled into moving around almost on auto-pilot. They become an extension of your sense of awareness from daily use. It is only when the banality of routine is disturbed that you realise you are in a different space. For years, I walked from Waterloo Bridge into Strand and Aldwych in central London without glancing at the signs or traffic: I knew exactly when to stop and go, unconsciously taking in the bustling traffic. But few days ago, just as I crossed Somerset House and headed towards India House, the place was less familiar. I stopped to take in the new space: there was none of the heavy traffic rushing from the right; instead, the road was closed to traffic, permanently, the space transformed into a pedestrian zone and a pocket park with new crossings — and something else was different: the air felt slightly less polluted. It is one of the busy spaces transformed to rejuvenate and refresh not only the air, but also business, health and culture.

If you come from major capitals of air pollution, you would find that London’s air is refreshingly clean; it is all relative, of course. Vast, verdant green parks co-exist with smooth moving traffic above and below the ground as millions of people live their lives across buzzing business and residential areas. Yet, recent research suggests that toxic air contributes to the premature deaths of nearly 4,000 Londoners every year. Air pollution is estimated to affect every borough, not just central London. In 2013, Ella Adoo-Kissi-Debrah, a nine-year-old girl who lived near the South Circular Road near Lewisham, south-east London, died following an asthma attack, becoming the first person in the United Kingdom to have air pollution listed as a cause of death in the coroner’s report. Her death added a new urgency to measures to deal with pollution, mostly led by the mayor, Sadiq Khan. As experts say, all Londoners live in areas that breach the World Health Organization (WHO) target for particulate matter and nitrogen dioxide.


People living along or near major roads are particularly vulnerable, and officials of Transport for London (TfL) — the apex body responsible for transport in the capital — admit that road vehicles are the single biggest cause of air pollution. They produce nearly half of all nitrogen oxides and emit tiny particles of rubber and metal into the air, too small to see with the naked eye. Despite recent improvements in air quality, air pollution remains the biggest environmental risk to the health of all Londoners, worsening chronic illnesses such as asthma, lung and heart disease and putting the health of children at risk. Several charity groups and experts closely monitor the capital’s air quality, besides a network of monitoring stations set up by the London Assembly to provide real-time data, but challenges remain. In March, Khan issued a ‘high’ air pollution alert following “imported pollution from the continent alongside a build-up of local emissions”.

Since the office of London mayor was created in 2000, tackling air pollution has been one of its key tasks, and ‘road pricing’ the preferred way forward: levying charges to drive in some areas or to use vehicles of certain vintage. Today, there are three major charges in operation: Congestion Charge (since 2003), Low Emission Zone (2008) and Ultra Low Emission Zone (2019), each marked distinctly in the area of operation, the rules often tightened based on new evidence. In the first year of Congestion Charge alone, London enjoyed a 30 per cent reduction in traffic congestion and a 30 per cent increase in average speeds, while bus passenger numbers rose 38 per cent. Income raised through these levies are directly ploughed in to fund measures to curb air pollution and encourage green transport, such as creating new cycle lanes, more rapid charge points for electric vehicles and tighter emission standards for vehicles: Congestion Charge revenues increased from £316 million in 2020/21 to £423 million in 2021/22, and the expansion of ULEZ saw income rise from £77 million in 2020/21 to £226 million in 2021/22.


The targeted road pricing, alongside better sustainable travel alternatives, has transformed air quality and transport in London, but there is still much distance to travel. The mayor’s transport strategy released in 2018 has a target of 80 per cent of London journeys being made in 2041 by cycling, walking or public transport. Last year, the cost of traffic congestion to London’s economy was estimated to be £5.1 billion.

Each of the three charges is levied in specified zones. The Congestion Charge zone covers the busy central London. The ULEZ zone was previously same as the Congestion Charge zone, but Khan expanded the ULEZ area in October 2021 to cover a quarter of London and is now the largest zone of its kind in Europe; there are now plans to extend the ULEZ to the entire patch of Greater London from August 2023. The LEZ zone covers most of Greater London. The Congestion Charge is a £15 daily charge to drive within the charge zone. Vehicles that do not meet strict emission standards in the ULEZ area must pay a £12.50 daily charge to drive inside the zone, and to drive in the wider LEZ zone, heavy vehicles, most running on diesel, need to meet the emission standards or pay penalties that range from £100 to £300 per vehicle. The three charges are monitored by a dense network of cameras across London through automatic-number plate recognition technology. There are also calls to set up a national scrappage scheme to support motorists to switch to cleaner vehicles that comply with strict ULEZ standards.

Khan says: “In London, traffic emissions are the biggest source of poor air quality. That’s why we introduced the world’s first Ultra Low Emission Zone (ULEZ) in 2019, which operates 24 hours a day, seven days a week. This has already made a swift and significant difference in central London. But the job is far from done. There are two main air pollutants of concern in London, based on their impact on human health: nitrogen dioxide (NO2) and particulate matter (PM2.5). And while significant progress has been made on NO2, we must go further — tens of thousands of Londoners are still breathing air that’s more polluted than the legal limits, and 99 per cent of Londoners live in areas exceeding the recommended guidelines from the WHO, which are much tighter than the legal standards”.

The Congestion Charge applicable to all vehicles in central London has been widely welcomed, but has also led to a tricky diplomatic issue. A large number of high commissions and embassies based in the zone refuse to pay the charge for using their cars and vehicles on the ground that it is not a ‘charge’ but a ‘tax’, and under the 1961 Vienna Convention on Diplomatic Relations, they are exempt from the ‘tax’. London’s transport officials disagree, liaising with the Foreign Office to take up the issue, but the latest estimate of outstanding debts owed by the foreign missions is £142 million (topping the list is the United States embassy, at £14.6 million). Says Paul Cowperthwaite, Transport for London’s General Manager for Road User Charging: “We are clear that the Congestion Charge is a charge for a service and not a tax. This means that foreign diplomats are not exempt from paying it. We continue to pursue all unpaid Congestion Charge fees and related penalty charge notices.”

Recent research shows “huge progress” in improving air quality by measures such as targeted road pricing, but experts believe that putting in place ULEZ alone will not ensure sustainable improvements in air quality. A study by Imperial College London found ULEZ reducing London’s nitrogen dioxide levels by a few per cent during the first few weeks of its implementation, but researchers say their findings highlight that ULEZs are “not a silver bullet”, and that sustained improvements in air pollution require multiple measures. Researcher Marc Stettler says: “Cities considering air pollution policies should not expect ULEZs alone to fix the issue as they contribute marginally to cleaner air. This is especially the case for pollutants that might originate elsewhere and be blown by winds into the city, such as particulate matter and ozone”.

Along with the three road charges, transport officials have ensured that London’s core bus fleet meets ULEZ standards, and have introduced over 500 electric buses and new hydrogen double-deck models, complementing efforts to get more Londoners cycling, walking, using public transport or investing in newer, cleaner vehicles, such as electric cars. Cycling, which is already a thriving sub-culture in London, has received more funding under plans to tackle air pollution.

London is not yet the cycling capital of Europe. There are cities where cycling is a major mode of transport, such as Copenhagen, Amsterdam and Paris, but cycling has more than doubled in the capital since 2000. Transport officials are working on a vision to make London the world’s best big city for cycling. On average, cycling levels across the Capital rose by 5.8 per cent per year from 2000-2017, and there was an overall 24 per cent increase between 2012 and 2017, figures show. People can collect a cycle at any of the cycle stands across the capital, complete their journeys, and leave them at designated points. One of the most popular initiatives of the former mayor, Boris Johnson, was the introduction of what have come to be known as ‘Boris bikes’, encouraging more people to abandon cars and public transport, and use the healthier and greener option. There has also been a significant decrease in the risk of being killed or seriously injured while cycling in London since 2000. A Cycling Infrastructure Database enables riders to plot and plan their routes, and park cycles after completing journeys.

Says Will Norman, Walking and Cycling Commissioner: “For too long we’ve heard that people cycle more in countries such as Denmark and the Netherlands because it’s part of their culture, or because it’s flat, or because the cities there are compact. But none of those are the reason why cycling is more popular in these places. In truth, these cities see more cycling because their streets have been designed to prioritise people, not cars. It’s easy to forget that in the early 1970s, Amsterdam was much like London today: choked with traffic, filled with parked cars and with only a fraction of people cycling to get around. How the city works now is the result of the previous generation’s political choices. Cycle around London today and you will start to see glimpses of what happens when streets are designed to enable everyone to cycle: mums with babies cycling through Vauxhall; businessmen in suits gliding through Bank Junction on the way to meetings; children pedalling over Blackfriars Bridge”.

New research by campaign group ‘Friends of the Earth’ suggests that people from non-white communities in England are over three times more likely to live in neighbourhoods with very high air pollution, putting them at disproportionate risk of heart attacks, cancer and strokes. The study based on official statistics shows that minority ethnic people make up nearly half the populations living in areas where average levels of nitrogen dioxide (NO2) or small particulate matter (PM2.5) were double the WHO guidelines. Conversely, the areas with the cleanest air were the whitest, with fewer than one in 20 people from the areas with pollution within recommended levels hailing from a minority ethnic background.

Says Khan: “I also see tackling air pollution as an urgent issue of social justice. Londoners on lower incomes are more likely to live in the areas most badly affected by air pollution and least likely to own a car… The decisions we make now to tackle air pollution in our cities are a matter of life and death. It took decades before action was taken to protect children from toxic cigarette smoke. We cannot make the same mistakes by turning a blind eye to the clear evidence showing the dangers of toxic air pollution. That’s why I’m more determined than ever to continue taking bold action in London to accelerate our efforts to clean up our air, and I encourage other cities in the UK and around the world to do the same. Everyone has a right to breathe clean air — and we must not stop until this becomes a reality”.


More news from