China's alleged 'Fentanyl King' and the Mexican cartels

Kate Adie introduces stories about China's alleged 'Fentanyl King', how Odesa's famous sense of humour is responding to Russian attacks, Delhi's new EV push, and rising child obesity rates in southern Italy.

After Zhang Zhidong graduated from China's most-prestigious university, he moved to Mexico to find work. Years later, US law enforcement named him as a key figure working with Mexican cartels in the booming fentanyl trade. Now awaiting trial in a Brooklyn prison, Zhidong denies the allegations against him. Shawn Yuan travelled to Mexico to speak to cartel about the man they knew as 'Brother Wang', to chart the origin story of the man US authorities claim is the 'Fentanyl King'.

The Ukrainian port city of Odesa is renowned for its sense of humour - and it's still apparent even as Russia ramps up attacks in its efforts to strangle Ukraine's commercial links with the rest of the world. Paul Adams has been speaking to residents trying to continue life as normal amid the daily strikes.

Faced with soaring pollution levels, Delhi's regional government is making a concerted push to get more people into electric vehicles - becoming the first Indian city to plan on phasing out petrol-fuelled scooters, bikes and auto-rickshaws from its roads. Arunoday Mukharji found the city's delivery drivers sceptical of the plan.

Naples has long been famed for its healthy diet, but recently restaurants and cafes have adapted their menus for a changing market - and the rising demand for processed fast food. Teenagers have been most affected by the new trend and the region is now seeing soaring rates in childhood obesity, as Sofia Bettiza discovered.

Series producer: Serena Tarling Production coordinators: Katie Morrison and Sophie Hill Editor: Richard Fenton-Smith