Hidden in the sinewy alleyways of north-east Delhi lies a derelict garage. By day, it is home to a perfunctory soap dispensary business, where a handful of workers assemble umpteen containers. By night, the brother-owners and their protégé Salik toil away at healing Delhi’s abundant bird life.

The year is 2020. Nadeem and Saud, siblings and lifelong Delhites, tune out the eruptive sounds of demonstrations pervading their neighbourhood. This working-class, largely Muslim area has become the epicenter of protests against the Citizenship Amendment Act, a controversial bill that excludes Muslims in South Asia from the right to refuge in India.

With impassioned calls over megaphone to Indian secular values in earshot, Nadeem’s family half-jokingly ponder whether they should choose neighbouring Pakistan or Bangladesh as their refuge once they’ve escaped the country. To shake off such disturbances, the brothers turn to animal healing as their pass-time, rescuing kites from all corners of the metropolis – landfills, reservoirs, local terraces – to perform DIY surgeries and nurse them back to health.

The city’s kites are crucial to its environmental functions, snacking from the top of a 15-tonne garbage heap at one of the world’s largest landfills. As the protagonist Nadeem puts it: ‘The city is a stomach. The birds are the microbial gut.’ But the dramatically declining air quality – India’s coal usage has doubled in the last decade – is rendering the birds ill, and causing them to drop from the sky like flies.

Working through endless power cuts, a garage flooded with sewage water in monsoon season and crumbling in-roads, this Wildlife Rescue is swimming against the tide of India’s well-documented environmental decline. With odour-ridden drinking water, appalling air quality and the overflow of garbage around urban settlements, conditions around the workshop are viscerally grim.

If the ill-health of bird life is any kind of harbinger for humankind, All That Breathes is a clear warning for the future of global health. But the tenor of this documentary stops short of alarmist – opting instead for a song-like meditative quality. Its slow-moving, Blue Planet-like footage of owls, kites, birds and pigs tied together with Nadeem’s contemplations about the future of his city is worth marveling at. An ethereal soundtrack coupled with slow, naturalistic observation prove to be a tonic to the clinical and statistical treatment often given to climate reporting.

This patient method appears to offer director Shaunak Sen a parallel insight in to India’s political disorder. Told through poignant testimony, the wildlife rescuers explain their gravitational pull towards bird healing, but small moments of fear for anti-Muslim violence prize through their quotidian existence during the Delhi riots of 2020. Slow storytelling – though difficult to adjust to in an attention-scarce age – offers a tangible feeling for how social and environmental devastation run in parallel.

Oscillating between moments of hope and despair, the characters think of their future. The question of their premature deaths hangs in the air. On bad days, Nadeem mulls over the possibilities for Delhi’s wildlife and human life – both are dwindling. On other days, he spells out his own particular, moving vision of solidarity – a form that goes beyond rescuing the liberal nation. Nations seem absurdly abstract compared to the hard problem of living beings struggling to breathe. For Nadeem, ‘you don’t care for people because you share a country, identity or religion with them. Life itself is kinship. It is a community of air.’

All That Breathes is filmmaker Shaunak Sen’s second documentary as a director. In it, he presents a moving observation, that even in times of strife, when the working classes are squeezed to astonishing limits, forms of mutual aid – even inter-species aid – will flourish.