By Chris Morris
BBC News, Chennai
The presence of Tamil Nadu's leaders is felt country-wide
As the evening light begins to fade, a Bharatanatyam dance begins at the Kapaleeswarar temple in the heart of Chennai (Madras). A drummer beats out the rhythm and the dancer's eyes dart from left to right.
Now India's most popular classical dance, this ancient art originated in the temples of Tamil Nadu, and is a powerful expression of Tamil and Dravidian culture.
Tamils in India are proud of their identity and their desire to express it has extended into politics for a long time.
Both the main parties in this state - the DMK and the AIADMK - are Dravidian-based, and don't take part in elections anywhere else.
"For years now it has been a Dravidian party which has come into power," says Hyma Ramakrishna, who is watching the dancer perform, "and I don't think that will change.
Tamil Nadu has its own distinct culture
"Years ago it was the Congress party from the central government which was ruling even over Tamil Nadu. But the Dravidian movement is too strong now
(and) that is the way people vote."
Alongside the dance, a Tamil Hindu religious festival is under way in the temple grounds. There's a riot of noise and bucket-loads of flowers are being carried along as offerings to Lord Shiva and his consort Parvati.
This is recognisably India, but it is a different place from the big cities further north and that has its own political effect as well.
"People in Tamil Nadu will say I'm a Tamilian first, but I'm also an Indian," says VV Sunderam, a Tamil businessman who divides his time between Chennai and the United States.
"They vote on local issues, and they express their local identity. But they also know they have tremendous influence on who becomes the prime minister in Delhi. Tamil Nadu is really one of the kingmakers in national politics."
On Chennai's sea front the statue of Mahatma Gandhi - the national icon - stands in pride of place.
Tamil Nadu's influence over India is growing stronger
But neither of this state's most powerful politicians - the former film script writer Karunanidhi of the DMK, and the former actress Jayalalithaa of the AIADMK - is actually standing in this election.
Their national power stems from their local strength.
So why is it that politics in Tamil Nadu has become so distinct?
"Initially it was separatist or secessionist at least in words," says N Ram, editor-in-chief of the Hindu newspaper. "And when they gave that up they had a clear framework for demanding rights for the states and greater autonomy.
"But then it's a paradox," he adds, "that on the national scene these regional parties play a crucial role. They capitalise on it and convert it into material gain."
The markets in the city centre are full of people bargaining for jewellery and saris. But the hard political bargains have yet to be struck.
In one of the closest and most unpredictable elections for years, Tamil Nadu will send 39 MPs to the next parliament in Delhi.
It's a potentially decisive bloc because historically voters here tend to hand big victories to one side or the other.
So people in this state know that if either of their main regional parties sweeps this election - last time it was a DMK-led alliance, this time could be different - then it will be in pole position to help form the next Indian government in Delhi.
The lesson from Chennai is that this is a national election in which the role of states and regions grows ever stronger.