Just before this BBC podcast gets underway, here's something you may not know.

My name's Linda Davies and I Commission Podcasts for BBC Sounds.

As you'd expect, at the BBC we make podcasts of the very highest quality featuring the most knowledgeable

experts and genuinely engaging voices. What you may not know is that the BBC

makes podcasts about all kinds of things like pop stars,

poltergeist, cricket, and conspiracy theories and that's just a few examples.

If you'd like to discover something a little bit unexpected,

find your next podcast over at BBC Sounds.

Thanks for downloading this shorter World Service version of the program.

We hope you enjoy it. It. Hello and welcome to more or less on the BBC World Service.

We are your weekly guide to the numbers. and welcome to more or less on the BBC World Service.

We're your weekly guide to the numbers all around us,

in the news and in life, and I'm Tim Harford. The OCLL Hong Kong is hardly a name to conjure with, but it's the largest container ship in the world.

If you stood it on its stern, propped up against the Empire State Building,

the prowl would be higher than the building itself.

It's one of the so-called Type E class ships which have transformed shipping,

allowing more and more stuff to be transported more and more cheaply around the world.

The ships have gotten so big they've had to expand the Panama Canal to accommodate them.

All this progress has come at a price.

The super ships have super engines which in turn produced lots of pollution.

So much so that the following headline was popping up across the internet.

World's 15 largest ships emit more pollution than all the world's cars.

...