Air pollution, a wildlife manifesto and autumn colour – green news roundup

A new study has linked air pollution to a much greater risk of dementia. Photograph: Nick Ansell/PA

Environment news

• UN environment chief criticised by UN over frequent flying

• Build walls on seafloor to stop glaciers melting, scientists say

• UK pledges £2.1m to save Asian tigers and African chimpanzees

• EU must end new petrol and diesel car sales by 2030 to meet climate targets – report

• Microplastics can spread via flying insects, research shows

• Air pollution linked to much greater risk of dementia

• Two directors quit key fracking firm amid ‘Tory rebellion’ claims

• Germany launches world’s first hydrogen-powered train

• Air pollution particles found in mothers’ placentas

In depth

• ‘I was horrified that children are breathing air this dirty inside the school’

• Chris Packham: My manifesto could save Britain’s dying wildlife

• Sadiq Khan says he’s better than Boris on cycling – but do his claims add up?

• Long hot summer means we should enjoy spectacular autumn colour

• ‘Treating protest as terrorism’: US plans crackdown on Keystone XL activists

Multimedia

Flamingos at a bird sanctuary in Tunisia. Photograph: Anadolu Agency/Getty Images

• Seven endangered species that could (almost) fit in a single train carriage

• The week in wildlife – in pictures

• Ciwem environmental photographer of the year 2018 winners – in pictures

And finally …

Arachnophobes look away now … this Greek beach was found covered by a 300m-long spiders’ web