From fighting discrimination and dowry to exhorting youth to shun drugs and be eco-friendly, these Bollywood celebrities make a difference to people's lives in a variety of ways.

It takes guts to back the truth. And Bollywood has shown time and again that when it comes to championing a cause, it is no chicken. Definitely, the platform has never been as large as with actor-director-producer Aamir Khan's new TV show — Satyameva Jayate, but the ‘causerati' in Bollywood have always been active on issues ranging from HIV to homosexuality, from being eco-friendly to being human. Here are some of the top crusaders in Bollywood:

Aamir Khan

Without a doubt, this man has not just made people wake up early on Sunday mornings to serious issues such as female infanticide, child sexual abuse and dowry, but also managed to ruffle feathers in the government. But even before his show Satyameva Jayate, Aamir was seen as a do-gooder.

He openly came out in support of Medha Patkar for the Narmada Bachao Andolan. During Anna Hazare's fast-unto-death movement in favour of the Lokpal Bill, Aamir expressed his solidarity by being present on location. Aamir's advertisements for the Incredible India campaign exhorting Indians to preserve our heritage sites and treat tourists with respect, was yet another feather in his cap. He is also the national brand ambassador for UNICEF to curb malnutrition in children.

Even through his recent films, Aamir has been associated with some cause or the other; from raising children to be unique individuals (“Taare Zameen Par”) to unsettling the education system (“3 Idiots”) to questioning government intentions (“Rang De Basanti”), Aamir's films have brought thinking back to Hindi films.

Celina Jaitley

Not many can get past supporting the LGBT community (Lesbian, Gay, Bisexual and Transgender) without inviting doubt over one's own sexuality. Celina Jaitley too faced accusations of being lesbian when she proposed the abolition of Article 377 of the Indian Penal Code (IPC), which criminalised homosexuality. Now as a mother of twins, Celina may not have the time to give to this cause, but she is the frontrunner in fighting for gay rights. She has appeared several times on national television channels, debating with people who oppose the abolition of Article 377. She is also an animal rights' activist and has posed for PETA's campaigns against the All India Institute of Medical Sciences' reported ill-treatment of animals.

Rahul Bose

Rahul Bose could easily be the actor most involved in social activities. In 2007, he started a non-profit organisation, The Foundation, dedicated to the removal of discrimination through education and awareness. His NGO deals with the marginalised communities and with victims of child sexual abuse. He is also a go-green advocate being Oxfam's first Global Ambassador from the Eastern Hemisphere and being associated with Planet Alert that engages in creating awareness about climatic change through college interactions, mass media campaigns and a video as well as a blog. Post the tsunami, he made several trips to the Andaman & Nicobar Islands to provide relief and was awarded the Godfrey Phillips Prize for Bravery in Social Service.

Priyanka Chopra

As part of her role as the brand ambassador for the NDTV green Marathon, last month Priyanka Chopra was seen personally cleaning the filth from the banks of the Yamuna in Agra. Earlier this year, she pledged her dedication towards making the youth shun drugs by associating with a programme called Awakening Youth against drug addiction. Besides, the actor was part of the Save The Children campaign post the flash floods in Leh in 2010.

Nandita Das

Nandita Das completed her Masters in Social Work from the University of Delhi and worked with various NGOs. Though she acts and directs, she continues to advocate issues of social justice through various platforms. Nandita's films are her voice. From her first English film “Fire” (which brought homosexuality to Indian screens for the first time) to her directorial debut “Firaaq” (which dealt with the post-Godhra riots in Gujarat), Nandita speaks her mind. She also plans to campaign for child survival, against AIDS and eliminating violence against women.

Amitabh Bachchan

Amitabh is well aware of his clout and has put it to good use to create awareness and galvanize his fans into action. UNICEF's Pulse Polio Campaign has him mouthing four crisp words — Do boond zindagi ke, in the most effective manner. While not much is known about this, it is learnt that the Big B also contributes silently to causes that require funding and that some welfare funds for the 2001 Latur earthquake and the 2004 tsunami survivors were supported by him.