"I already had an inclination to protect the environment, and then one fine day I saw huge patches of plastic and filth on the beach from my balcony," Shah told the Washington Post. "The amount of plastic on the beach had to be seen to be believed. It was a horrendous and disturbing sight."
Instead of telling himself it was the government's job to deal with the problem, Shah contacted his 84-year-old friend and neighbour Harbanash Mathur.
Mathur "instantly agreed to join issues with me and help in the cleaning," Shah said. "That's how the journey began. The first cleanup was done by me and Mr Mathur alone."
It wasn't long before others began joining in. Through word of mouth and social media, other citizens gradually began to join the cause. There are currently about 200 volunteers, altogether, according to Shah.
Mathur has since died, following a battle with cancer. But his legacy has only continued to grow. Now, the Versova Resident Volunteers, as they've dubbed themselves, meet every weekend to chip away at the vast piles of plastic and other garbage strewn along the beach. And they're making impressive headway. In the 45 weeks since Shah first got started, the volunteers have succeeded in removing more than 4 million pounds of litter from the shore.
Most of it is plastic that's washed in from the ocean, Shah said, but added that some of it is also the result of people littering along the beach. Additionally, several nearby sewer lines carrying sewage out to the ocean also deliver a fair share of plastic on the shore. The volunteers have been known to collect everything from condoms and tobacco pouches to children's school bags.
And they've attracted international attention in the process. Just a few weekends ago, Lewis Pugh - renowned distance swimmer and the United Nations Environment Programme's Patron of the Oceans - visited Mumbai and joined the volunteers on the beach.
As severe as the problem at Versova is, though, it's far from the only beach suffering from a trash problem. Plastic pollution is a growing threat to the world's oceans, and one that's garnering rising concern from marine biologists.
An oft-cited 2015 paper in the journal Science estimated that anywhere from 4.8 to 12.7 million tonnes of plastic waste may have been poured into the ocean in the year 2010 alone. And another recent study suggested that by the year 2050, the amount of plastic in the ocean might outweigh the fish.
All this plastic has manifested itself in some pretty visible ways. It's notorious for entangling or choking marine animals unfortunate enough to mistake it for food, and it's also responsible for monstrosities such as the Great Pacific Garbage Patch - a huge, swirling vortex of marine debris in the North Pacific Ocean.
Especially dangerous in the eyes of marine biologists are microplastics - bits of plastic that have broken down into smaller and smaller pieces over time, some eventually getting so small they can't even be seen with the naked eye. The oceans are teeming with these tiny plastic bits, and scientists believe they're capable of causing all kinds of adverse effects in animals who happen to swallow them.
The mounds of debris at Versova Beach are just one testament to the seriousness of the world's plastic problem. But Shah and his volunteers hope to make a difference by collecting as much plastic as possible while it's still on the shore, before it can be washed back out to sea.
"We are ocean lovers, and our engagement will continue with the beach and ocean till our oceans are clean," he said.
And in a recent statement to the Versova volunteers, UNEP executive director Erik Solheim echoed his sentiments.
"Up to 13 million tonnes of plastic and crazy amounts of other rubbish end up in our oceans every year," he said.
"If you look at the thousands of tobacco pouches or discarded schoolbags washed up here, it is a sad reflection of a society's lack of understanding on the implication of their actions. We are damaging our environment, our food chain and our health in ways that we have not even begun to understand. But each one of us has the power to turn that around. We can stop it at source, in our homes and on our beaches."