The High Court's air pollution ruling - what you need to know:

London has some of the worst air pollution levels in the UK - and a third runway at Heathrow and Brexit will only make them worse.

London has the worst levels of air pollution in the UK - air pollution levels that cause as many as 10,000 premature deaths a year.

It's a real public health emergency in our city.

And you'd think that would make tackling it one of the Conservative Government's top priorities.

Unfortunately, as the recent High Court ruling showed, you'd be wrong.

Environmental lawyers, Client Earth, took the Conservative Government to court to challenge their sluggish efforts to meet EU air pollution targets - efforts the judicial review described as "woefully inadequate".

Here are the three things you need to know about today's ruling:

1. A third runway at Heathrow will only make air pollution worse

Air pollution near Heathrow is some of the worst in Europe, in every one of the last ten years, pollution levels have been breached. A 3rd runway means more flights and more air pollution concentrated on one spot in London.

Damningly, the Airports Commission has also been unable to demonstrate how Heathrow could be expanded whilst meeting health-based legal air quality levels.

There's just no way to expand Heathrow and add more flights without making dangerously high air pollution levels worse - and that's one of the many reasons we're opposed to a third runway at Heathrow (if you agree with us, add your name here:

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2. Leaving the EU could mean the Conservative Government disregards air pollution targets

The targets the Conservative Government are, so far, failing to meet, are set by the EU. There are no guarantees that if we leave the EU, the Conservative Government will maintain the (very sensible) European air pollution targets. 

The Conservative Government is already failing to meet these targets - and without the help of Europe to set and enforce them, they might well just revert to their current "woefully inadequate" plans.

The air pollution targets are there to save lives and improve people's health - we can't afford any complacency.

3. If we don't get serious about this, more people will die prematurely

Air pollution is a real, serious, public health problem. 10,000 people in London die every year prematurely because of it and without serious, urgent action, that will only get worse.

This Conservative Government has shown, time and time again, that they just aren't taking it seriously - by their actions to meet it so far and by greenlighting a third runway at Heathrow, which will only make the problem worse.

The Airports Commission has been unable to demonstrate how Heathrow could be expanded whilst meeting health-based legal air quality levels.

It's a simple fact that only the Liberal Democrats are united in fighting against Heathrow expansion and to ensure vital European air quality limits are not scrapped by this Conservative Brexit Government.

If you want action on air pollution and Heathrow, it's got to be Sarah on Thursday 1st December.