(A supporter of India’s main opposition Bharatiya Janata Party (BJP) wears a hat and goggles supporting the party’s lotus symbol during a rally being addressed by Hindu nationalist Narendra Modi in Agra November 21, 2013. REUTERS/Anindito Mukherjee)

Prime ministerial hopeful Narendra Modi used a large rally in India’s historic city of Agra on Thursday to push his Hindu nationalist agenda in a key election state where the sizeable Muslim minority eyes his campaign with alarm.

With a bigger population than Russia and 80 parliamentary seats up for grabs, the northern state of Uttar Pradesh (UP) is seen as a must-win battleground for Modi in a national election expected to start by April.

The rally in Agra, where tens of thousands of people filled a dusty field outside the centre of the city that boasts the Taj Mahal, was Modi’s fourth visit to the state in the last month or so, underlining its importance.

The 63-year-old, whose gruelling campaign has put him in pole position to lead the world’s biggest democracy, attacked the ruling Congress party for pandering to minorities – making indirect references to majority Hindus and minority Muslims.