By Geeta Pandey, BBC

A photograph of a paramilitary policeman swinging his baton at an elderly Sikh man has become the defining image of the ongoing farmers' protest in India.

The photograph, taken by Ravi Choudhary, a photojournalist with Press Trust of India (PTI), has gone viral on social media.

It has also resulted in political wrangling - with opposition politicians using the image to criticise the way the protesters are being treated and Prime Minister Narendra Modi's Bharatiya Janata Party (BJP) claiming - falsely - that the farmer was not hit.

Hundreds of thousands of farmers have laid siege to Delhi for the past few days, choking almost all the entry points to the national capital.

They are protesting against a recent law that they say is against their interests. The government says the reforms, which open the farming sector to private players, will not hurt farmers.

Unconvinced, thousands of them have marched upon Delhi, where they were met by barricades at the border.

As they arrived in a convoy of tractors and on foot, tens of thousands of police and paramilitary troops were deployed to halt their march, leading to clashes with the police.

In several places, police fired tear gas shells and used water cannons to try to beat them back.

Farmers removed police barricades in protest

The photograph of the Sikh farmer, with a flowing white beard, being threatened by a paramilitary policeman was taken last Friday at the Singhu border in north-west Delhi as farmers and protesters breached the barricades and entered the city.

"There was stone pelting, barricades were broken and a bus was also damaged with violent clashes between the police and protesters," photojournalist Ravi Choudhary, who took the picture, told fact-check site Boomlive.com.

He said the police started hitting the protesters and the old man in the photo was also hit.

The photograph went viral quickly, shared by tens of thousands of people on Twitter, Facebook and Instagram.

Many, including the photographer, tagged the image with "Jai Jawan, Jai Kisan" (or "Hail the Soldier, Hail the Farmer") - a slogan coined by former Indian PM Lal Bahadur Shastri in 1965 during the India-Pakistan war to stress the importance of soldiers and farmers in nation building.

Rahul Gandhi, senior leader of the opposition Congress party, also tweeted the image.

"It's a very sad photo. Our slogan was Jai Jawan, Jai Kisan, but today PM Modi's arrogance has pitted the soldier against the farmer. This is very dangerous," he wrote.

बड़ी ही दुखद फ़ोटो है। हमारा नारा तो ‘जय जवान जय किसान’ का था लेकिन आज PM मोदी के अहंकार ने जवान को किसान के ख़िलाफ़ खड़ा कर दिया।

यह बहुत ख़तरनाक है। pic.twitter.com/1pArTEECsU

— Rahul Gandhi (@RahulGandhi) November 28, 2020

Amit Malviya, head of the BJP's IT cell, questioned Mr Gandhi's claim - he shared a three-second video clip to claim that the farmer had not been hit and described it as propaganda.

Rahul Gandhi must be the most discredited opposition leader India has seen in a long long time. https://t.co/9wQeNE5xAP pic.twitter.com/b4HjXTHPSx

— Amit Malviya (@amitmalviya) November 28, 2020

In the end though, it was his tweet that was called out for being propaganda - many pointed out that it was labelled "manipulated media" by Twitter.

Mr Malviya's claims were also debunked by Boomlive which scoured longer versions of the video and also tracked down Sukhdev Singh, the farmer in the photograph, and interviewed him.

It reported that the farmer was "targeted by not one but two security personnel… Mr Singh who is currently at the Haryana-Delhi border told us that he sustained injuries to his forearm, back and calf muscle".

Images of thousands of elderly farmers from Punjab and Haryana - known as the "food bowl" of India - being tear-gassed and sprayed with water in the winter cold have won them tremendous public sympathy in India and also from the diaspora around the globe.

On Monday, Canadian Prime Minister Justin Trudeau expressed concern over India's response to the demonstrations and said his country "will always be there to defend the right of peaceful protest".

His comments drew a sharp response from India's foreign ministry which called it "ill-informed" and "unwarranted.

The farmers' cause, however, continues to gain support.

The authorities invited them for talks - one round of talks with government ministers on Tuesday failed; a second round is scheduled for Thursday.

The farmers have now set up massive camps at several locations on the city's border and say they will stay as long as it takes for the authorities to agree to repeal the "black law".

They say they've come "prepared for a long battle" - with trolleys full of rice and grains, and pots and pans to cook their own food.

It could be a long haul.