After leaving NID Ahmedabad, Sen got involved with the Narmada Bachao Andolan and worked closely with the activists and the displaced adivasis.

However, in the last decade in India, a loyal and serious readership of graphic novels and comic books has been developing gradually, and in 2022 Blaft Publications released a new edition of River of Stories, with a foreword by Arundhati Roy.

Sen's collaboration with Janam dates back to 1992 when he first designed the set, poster, and brochure for the production of Govind Purushottam Deshpande's Satyashodhak on the life and times of Jyotirao Phule.

Originally, they imagined establishing an outpost of sorts for comics culture in Delhi, from which they could reach out to and support creators in other cities and areas around the country.

The multimedia museum Virasat-e-Khalsa in which Sen's mural creation[13] is located was designed by renowned Boston-based architect Moshe Safdie.

It brings together "artists, designers, writers, teachers, students and interested members of the public to explore and document the complex life of the Mapusa Market in Goa from a variety of perspectives- illustrations, photographs, videos and interviews.

The project looked at how a historical market evolved and how it is coping with the challenges of globalisation, consumerism and supermarket and mall culture".