Dense fog and high pollution trigger alerts across London

London is facing a combination of dense fog and elevated air pollution at the start of the week, with forecasters and air-quality monitors warning of health risks for vulnerable people and the potential for significant disruption to travel across the capital and southern England.

Fog warnings extended as visibility plunges across the South East

A yellow weather warning for fog is in force across large parts of England on Monday 9 November 2026, stretching from Wales through the Midlands into eastern England and covering sections of London and the South East. Publicly available Met Office information indicates that the alert runs overnight into Tuesday morning, with visibility in some places expected to drop below 100 metres.

Reports from national broadcasters describe thick fog clinging to much of southern and eastern England at the start of the working week, following a similar warning on Sunday that already led to difficult driving conditions. Coverage from UK news outlets notes that dense fog was observed around key commuter corridors and open spaces in London over the weekend, and that the cloudy, still conditions are expected to persist into Tuesday in some areas.

The Met Office warning states that slower journey times and difficult travel conditions are likely, particularly during the morning peak. Public guidance highlights the possibility of delays to bus and rail services and advises road users to allow extra time, check local travel updates and ensure that lights and fog lamps are working before setting out.

Weather forecasts for Greater London show that fog and low cloud are slow to clear through Monday morning before brighter intervals develop later in the day. Light winds and overnight cooling are identified as key ingredients in allowing the fog to form and linger, especially in low-lying areas and around river valleys.

High pollution alert issued as fog traps emissions over the city

Alongside the fog warning, London’s air-quality alert system has triggered a high pollution notification for Tuesday 10 November. Local media reports indicate that City Hall has warned of elevated levels of particulate pollution, with particular concern for people living near busy roads and in dense urban districts.

Data from the government’s UK Air Information Resource shows that light winds and persistent fog have allowed pockets of moderate to high air pollution to build up over recent days, especially close to major traffic routes and in urban centres. The latest national forecast, issued on Sunday 8 November, noted that some locations in urban areas were already measuring very high pollution, while conditions elsewhere remained low away from the fog and larger towns.

According to local coverage in boroughs such as Hackney, the London alert system established by the mayor’s office sends notifications to schools, councils and registered individuals whenever moderate, high or very high pollution is forecast. For the current episode, those alerts emphasise the need for people with asthma, heart problems and other respiratory conditions to limit strenuous outdoor activity when pollution peaks, particularly during the morning and evening rush hours.

The combination of trapped vehicle emissions, domestic heating and stagnant weather patterns frequently leads to short-lived pollution episodes in London during autumn and winter. Historic assessments of the city’s air quality link these events to calm, high-pressure systems that cap the atmosphere and prevent pollutants from dispersing vertically, a pattern that mirrors the “perfect recipe” for fog described in recent national weather briefings.

Travel networks prepare for delays on roads, rails and at airports

Publicly available guidance associated with the current yellow warning highlights a range of possible impacts on the transport system. Road users are being advised to expect slower journey times, particularly on motorways and major A-roads serving London, as drivers reduce speed in response to poor visibility. Recent media reports have already noted multi-vehicle incidents in fog-affected areas of southern England over the weekend, underlining the risk posed by sudden changes in visibility.

Rail operators serving London have issued general advice through journey planners and social media to check services before travelling when fog warnings are active. Low visibility can require trains to operate at reduced speeds on certain stretches of track, potentially leading to knock-on delays during the busiest periods. Transport analysis produced for previous winters in the capital shows that signalling issues and congestion can compound the impact when dense fog coincides with the morning commute.

Air travel is also vulnerable in these conditions. Coverage from UK news outlets reports that flights at Heathrow experienced disruption on Monday morning as low cloud and fog reduced visibility on runways and taxiways. Under similar weather patterns in recent years, London’s airports have used low-visibility procedures, spacing aircraft further apart and occasionally suspending operations to maintain safety, a measure that can quickly lead to cancellations and missed connections for passengers.

Transport for London’s customer information policies state that disruption updates are shared through station announcements, roadside message signs and digital journey planners when weather-related problems are expected. Travellers planning to use suburban rail, Underground services or airport links during the current fog episode are being urged in public messaging to allow more time and to check real-time updates before departing.

Health advice for residents and visitors during the pollution episode

National health guidance on air quality recommends that people with existing heart or lung conditions monitor official air pollution indices and follow tailored advice during high episodes. For London’s current alert, information from government and local authority sources advises those who notice symptoms such as coughing, wheezing or shortness of breath to consider reducing physical exertion outdoors and to keep necessary medications, including reliever inhalers for asthma, close at hand.

The UK’s air-quality index divides pollution into low, moderate, high and very high bands. In the high band, general population health risks remain relatively small for short-term exposure, but people with underlying conditions may experience worsening symptoms, particularly if they are active outside for extended periods. The latest London forecast suggests that the highest concentrations are expected near main roads and during peak traffic times, while parks and less built-up areas are likely to experience somewhat lower levels.

Public information issued in previous London alerts encourages schools and childcare settings to consider adapting outdoor activities for sensitive children when high pollution is forecast, for example by shortening outdoor playtimes or moving more vigorous exercise indoors. Similar messages are often directed at older adults and those recovering from respiratory infections, advising them to seek cleaner-air routes, avoid standing near idling traffic and, where feasible, time essential journeys for periods when pollution is expected to ease.

Visitors to London with no history of respiratory or heart disease are generally advised that they can continue normal activities, while remaining alert to any unusual symptoms. Health agencies highlight that most people will not experience significant effects during short, isolated pollution events, but recommend that anyone feeling unwell seek medical advice, particularly if symptoms persist after conditions have improved.

What the foggy, polluted conditions mean for upcoming days

Forecasts from the Met Office and the UK air-quality service indicate that the worst of the current combination of dense fog and elevated pollution is likely to occur between Monday evening and Tuesday morning. As daytime temperatures rise and winds strengthen midweek, visibility should gradually improve and pollutant levels are expected to fall back into the low to moderate range across much of Greater London.

Nevertheless, the latest outlook still points to the possibility of isolated pockets of moderate pollution persisting near the busiest transport corridors, particularly during calm periods overnight. Transport and weather agencies emphasise that warnings can be updated or extended at short notice if colder or more stagnant conditions develop again later in the week.

Longer-term reports on London’s transport and environment strategies underline the challenge of managing these episodes in a rapidly growing city that relies heavily on road traffic and intensive public transport. Policy documents from Transport for London and the Greater London Authority set out plans to reduce emissions through cleaner buses, expanded cycling infrastructure and restrictions on the most polluting vehicles, but acknowledge that weather patterns such as the current high-pressure system will continue to play a decisive role in short-term air-quality spikes.

For now, travellers and residents are being encouraged through public information channels to stay aware of the latest weather and air-quality updates, to plan journeys carefully and to take simple protective steps if they are particularly sensitive to polluted air. With calm, foggy nights still a feature of late autumn, London is likely to face further tests of its resilience to poor visibility and degraded air quality before winter sets in fully.