India's Rahul Gandhi takes over as president of opposition party

India's Rahul Gandhi took over on Saturday as president of the main opposition Indian National Congress party (INC), becoming the sixth member of the Nehru-Gandhi dynasty to head the party that has ruled the country for much of its independent history.

Fireworks erupted over the party headquarters in New Delhi drowning out the voice of his mother Sonia Gandhi as she handed over the reins of power to her 47-year-old son.

Gandhi, wearing a long flowing white kurta (traditional men's dress), smiled and waved from the dais adorned with posters of his late grandmother and father, former prime ministers Indira and Rajiv Gandhi.

Slogans of "long live Rahul" were shouted as hundreds of supporters danced to drum beats and burst firecrackers.

Gandhi was elected unopposed to take over from his mother who has been at the helm since 1998 following the assassination of her husband Rajiv. 

Sonia helped the INC win the general elections in 2004 and 2009.

But the party was swept out of office by Prime Minister Narendra Modi's right wing Bharatiya Janata Party (BJP) in 2014 and is now in a fight to win back support before a national election which must be held by 2019.

Gandhi has been party vice-president since 2013 and led its campaign for the 2014 election.

He was strongly criticised for what was INC's worst-ever showing as it lost power to Modi.

Since then, the party has lost polls in many states to the BJP, exposing Gandhi to further criticism.

On Saturday, Sonia was handed a memento by former prime minister Manmohan Singh as a token of appreciation for her "astute leadership" over the years.

Sonia led the party for 19 years. 

She has had health problems over the last few years, but the family and party have released little information about them.

Gandhi's father, Rajiv, his grandmother Indira and his great-grandfather Jawaharlal Nehru, have served as prime minister since India's independence from British colonialists in 1947.