London Mayor Sadiq Khan came to New York City this week to launch a new tourism campaign that aims to encourage New Yorkers and others to travel to the United Kingdom.

Shortly after arriving, he met with Pat Kiernan for an exclusive interview on the campaign.

The two also discussed congestion pricing. The policy has been in effect in London for nearly 20 years. After years of debate, congestion pricing is likely to begin late next year in Manhattan.

Khan said he believes congestion pricing is a necessity in all major cities to help reduce pollution and gridlock.

"In a city the size of London and New York, if everyone jumps in their car, the roads become gridlock. So, you've got to incentivize them to use public transport, to walk and to cycle. And by doing so, it improves the quality of the air," Khan said.

"But also, it means those cars, those vehicles that don't need to be on the road aren't on the road - which frees up the roads for those that need to use the roads."

Khan called the execution of congestion pricing as "massive success" and said that air toxicity in the center of London has dropped by 50% since the policy was introduced.

The mayor went on to say he believes that those who want to use a vehicle in London, but do not need to, should have to pay for the privilege to do so.

When asked if he thought that mindset was negatively affecting lower-income individuals who may not be able to afford to pay to drive into the city, Khan noted that that group is also most impacted by air pollution.

"Those who suffer the worst consequence from air pollution from the poison are those least likely to own a car. So it's an issue of social justice," he said. "And I'm a firm believer in the 'polluter pays' principle. If you pollute, you pay."