Now that the Ultra Low Emission Zone has officially expanded to cover all of Greater London, many are questioning what that means. 

The expansion, proposed by London Mayor Sadiq Khan, was created to help battle the region's toxic air and help improve the health of Londoners. 

Since it was first announced, the ULEZ has seen mixed reactions with some questioning if it is needed and if it will help Londoners. 

However, now that the ULEZ has expanded and millions more Londoners are covered by the zone, there are some key questions that need answering. 

Why has the ULEZ expanded?

According to TfL, the ULEZ has expanded to "help clear London's air and improve health."

It comes as research has shown that the poor air quality in London is "mainly caused by polluting vehicles."

News Shopper: This is what you need to know about the ULEZ.This is what you need to know about the ULEZ. (Image: PA)

The TfL shared that the latest data from the London Atmospheric Emissions Inventory showed that although "improvements are being made, road transport is the single biggest contributor of nitrogen dioxide and particulate matter emissions in Greater London."

Further knowledge is that air pollution is leading to the development of cancer, asthma and lung disease and a higher risk of dementia in older people. 

How do I pay the ULEZ charge and how much does it cost?

The ULEZ charge is £12.50 and runs 24 hours seven days a week apart from Christmas Day.

You can pay the ULEZ fee, via the official website, which is the TfL website you access via this link.

You can also pay automatically every month for any congestion charges and ULEZ charges via Auto Pay.

Is my vehicle ULEZ-compliant? 

You can look at the TfL website which lets you enter your number plate to check compliance. 

In order to avoid paying the charge, you need to meet the ULEZ emissions standards, meaning you must meet the required Euro emissions standards for your vehicle and emission type. 

Those standards are: 

Euro 3 for motorcycles, mopeds, motorised tricycles and quadricycles (L category)

Euro 4 (NOx) for petrol cars, vans, minibuses and other specialist vehicles

Euro 6 (NOx and PM) for diesel cars, vans and minibuses and other specialist vehicles

It's also important to know that for newer vehicles, the Euro emission standard may be listed in section D.2 of your V5C.