Nirmal's growing role as an activist can be seen in the successful ‘Save the Frogs' campaign against the local consumption of Indian Bullfrogs, which he led along with co-campaigner Clinton Vaz and the Goa Forest Department. The campaign included awareness-cum-law enforcement activities. He was also part of a team that worked on conserving the Bhimgad Forests in Karnataka. Their efforts ultimately led to the creation of the Bhimgad Wildlife Sanctuary. The efforts by his team under Nirmal's leadership also have helped declare the Mahdei Wildlife Sanctuary as a Proposed Tiger Reserve and bring attention to the Mahdei Dam Project that is slated to irreversibly damage prime Western Ghats habitat.