Plans for a low emission zone (LEZ) in Edinburgh could see drivers face "substantial" penalties in the city centre.

The city council has published its draft proposals to roll-out two LEZs by the end of 2020 - which will be subject of a public consultation. Grace periods will apply to allow motorists to prepare for the LEZ - with cars given until 2024.

Cars, buses and lorries that fail to meet pollution standards will be banned from the city centre.

A separate zone for the wider city will see cars exempt from the rules, meaning that pollution-emitting vehicles will still be able to sit in queues at the notorious St John's Road junction and other hotspots across the wider Capital.

The LEZ for the city centre does not include Queen Street, Haymarket and Tollcross. Buses, coaches and commercial vehicles will have until the end of 2021 to meet the city centre standards, while cars will have until the end of 2024 - and the car grace period could be extended to 2025.

If approved, the citywide LEZ would require buses, coaches and commercial vehicles to meet the pollution standards by the end of 2023 and cars would be excluded.

The proposals follow plans by the city council to introduce a free 'hopper' bus and extend tram lines in a bid to transform public transport in Edinburgh.

The free bus would take passengers around the city centre, while the tram route would head over North Bridge towards the BioQuarter and the Edinburgh Royal Infirmary.

Under the plans, the council hopes to reduce city centre traffic by up to 30% by treating cars as "guests" in a "pedestrian priority zone".

Transport and environment convener, Cllr Lesley Macinnes, said: "It's absolutely clear that there's an appetite for change around this. People recognise the issue.

"This is an ambitious low emission zone - there's no question about that.

"The climate change emergency is a heck of a push for us. We have to do it.

"We want to make sure that the way in which we do it doesn't negatively impact on those businesses and they are given enough time to respond and to come forward."

For petrol engines, vehicles will have to meet Euro 4 standards - required for vehicles sold after January 2006. Diesel cars will have to meet Euro 6 standards - required for diesel cars sold after September 2015. Heavy diesel vehicles will need to meet Euro 6 standards - generally those registered with the DVLA after 2014.

No details of the penalties for drivers who break the rules have been revealed but there will be "different levels of penalty charge depending on, for example, the class of vehicle or whether there are repeated contraventions".

Cllr Macinnes confirmed the penalties would be "substantial enough to change behaviour".

Exemptions are likely to include emergency, health service vehicles and historic vehicles.

The Scottish Government is requiring Edinburgh, Glasgow, Dundee and Aberdeen to establish LEZs. The council hopes its final plans will be ready to be implemented at the same time as legislation is agreed by the Scottish Parliament for a legal basis to introduce LEZs.

Cllr Macinnes added: "There will be continuity around the types of vehicles and the age of vehicles and standard of engines.

"There is a need to recognise the fact that Scotland's a relatively small geographic space. If we we were to implement something markedly different than Glasgow, we are setting up problems for businesses."

Addressing cars being exempt from the citywide LEZ, Cllr Macinnes said the plan was to tackle where most of the pollution was being created and hinted that including cars in the future was "an open avenue".

She said: "It's important for us to recognise where the problems are coming from at this point.

"We have to recognise what are the key sources of the problems. We are hitting those categories that makes the biggest difference fastest."