In the sleepy Goan beachfront town of Cansaulim, Angelo Fernandes and his neighbours stand guard in front of their 236-year-old church, watching a contractor haul away construction materials.

Hours earlier, local residents had been locked in a stand-off with railway workers sent to lay new track to transport coal through the community.

The showdown ended when local politicians intervened, work was suspended and the contractor pledged to remove the building materials. Mr Fernandes was there to ensure the contractor kept his word.

“Now we are wearing masks because of corona[virus], but if coal comes we’ll have to wear them forever,” he said.

The fiery encounter reflects growing anger in Goa against a government plan to turn the coastal state into a hub for the transport of coal through seaside villages and dense forests en route to large steel and power plants inland.

Companies such as JSW Steel and the Adani Group are using Goa’s Mormugao Port to import about 10m tons of coal from Australia and South Africa for use by heavy industries in neighbouring Karnataka state.

But Narendra Modi’s Bharatiya Janata party government is pushing for a massive expansion of the port’s coal-handling capacity to at least 41m tonnes a year by 2035.

To haul this huge quantity of coal from the port to industrial sites, authorities want to widen a highway and lay another track alongside the 153-year-old Portuguese-built railway line. The track runs through sensitive wildlife areas in the Western Ghats, mountains that have been recognised as significant biodiversity hotspots.

The existing line makes a steep climb through Bhagwan Mahaveer Sanctuary and Mollem National Park, passing in front of the Mandovi River’s spectacular 320m Dudhsagar Falls.

Goans are now mobilising to resist a project they believe will both expose local communities to large quantities of highly polluting coal dust, and break up a significant wildlife corridor that is home to panthers, leopards and other endangered species.

Angry flash mobs have forced the suspension of the double-tracking work in several locations over recent months.

“People are asking, ‘What’s in it for us?’” said lawyer Savio Correa, who lives near the Mormugao Port. He added that residents were already plagued by coal dust. “You want to carry coal, but are Goans benefiting, or are we sacrificing our health and our economy for the benefit of somebody else?”

Past talk of double-tracking the railway line was squelched by state-level politicians. In 2013, Goa’s top forest official described the wildlife sanctuary, adjacent to Mollem National Park, as a haven for “highly indigenous and endangered species . . . which will be completely disturbed” by adding an extra track.

But Mr Modi’s government has redoubled its efforts since 2016 as part of a national drive for “port-led” industrial development.

Contentious environmental clearances for the heavy infrastructure in the wildlife sanctuary were granted in a virtual meeting in early April, when Indians were still confined to their homes during a coronavirus lockdown. About 80 hectares of prime forest are now set to be destroyed.

Claude Alvares, director of the Goa Foundation, an environmental campaign group that has filed a lawsuit against the project, said New Delhi appeared to be acting at the behest of powerful corporates.

“Goa is the darling of the country because it’s the greenest place still left,” Mr Alvares said. “This is the place with priceless air. You don’t initiate a programme to fatally damage that air for the next 100 to 200 years.”

He added: “They say it is in the national interest. Our counter is that protecting wildlife is also in the national interest. We are constitutionally required to make sure wildlife is protected.”

Adani said it had “no plans of further expansion of operations” at Mormugao Port, adding that the facility still had spare coal-handling capacity.

“Existing infrastructure is only fulfilling the existential needs,” Adani said. “These allegations of pressurising the government are baseless.” JSW did not respond to requests for comment.

The furore is piling pressure on Pramod Sawant, Goa’s chief minister, caught between an angry public and the national BJP leadership’s development drive. After being criticised at a public gathering, he impetuously pledged coal handling at Mormugao would be cut by half.

But Goans remain wary. In the village of Kullem on the outskirts of the Bhagwan Mahaveer sanctuary, Manish Lambor, the local headman, said many residents depended on tourism for their livelihood, and feared their “world-class waterfall” would be destroyed. “If they disturb the waterfall, what will tourists see?” he asked.

Restaurateur Tribolo Souza, who lives just outside the Mollem National Park where authorities aim to build a four-lane highway, is furious. “The government of the day is not concerned about Goa,” he said. “They are all out to sell Goa.”