Bengali cuisine and culture is the least exported of all India's regions. More's the pity, says Chris Caldicott after sampling the sensory delights of Calcutta

"Calcutta bad country," muttered Raju as he slammed on the brakes to bring us to yet another violent halt. Before every one of these, there had been a brave lurch forward to gain a few more hard-fought yards of progress through the gridlocked traffic. Calcutta certainly has some bad sides, and traffic can be one of them. Yet given time, this intriguing city can be seductive and reveal many pleasures. After a few lurches more, we agreed to take a break and stop for lunch at Raju's favourite street café.

"Calcutta bad country," muttered Raju as he slammed on the brakes to bring us to yet another violent halt. Before every one of these, there had been a brave lurch forward to gain a few more hard-fought yards of progress through the gridlocked traffic. Calcutta certainly has some bad sides, and traffic can be one of them. Yet given time, this intriguing city can be seductive and reveal many pleasures. After a few lurches more, we agreed to take a break and stop for lunch at Raju's favourite street café.

Under a large board tree, that grows up through the broken pavement in a concrete isolation that seems to defy nature, a collection of wide wooden benches provide seating for a score of customers tucking into bowls of steaming freshly cooked spicy concoctions of vegetables, rice and dhal. The tree provides welcome shade, where men gather to meet and chat much like they do under trees in Indian villages. Many are taxi drivers; while they eat, grinning boys in shorts wash their cabs, their own bodies shiny with water. The food is delicious, delivered with impressive speed and very cheap. It is not, however, the traditional taste of Calcutta.

Bengali cuisine has long been hidden from tourists in the family kitchens of Calcutta's native population. The city's street cafés and restaurants have tended to cater to the tastes of migrant populations from other states of India or visitors from abroad. The emergence of a new generation of Bengalis, too busy to cook and with disposable income, is bringing the traditional dishes of local cuisine out into the public domain.

One of the essential tastes of the region is created by use of mustard oil and a spice mixture known as panch phoron or Bengali five-spice. The spices – mustard seeds, whole fenugreek, cumin seeds, nigella seeds and fennel seeds – are all fried together in equal quantities releasing their perfumes into the oil. The resulting aroma and flavour is familiar to many vegetable and pulse dishes that accompany the ubiquitous fish dishes of which Bengalis are so fond.

The black mustard seeds in this mixture are the only spice which is truly native to the region. Even before the British established Calcutta as an international port and the capital of their 18th-century Indian possessions, this coast of Bengal attracted traders from afar. Many were spice traders. Arab dhows came on monsoon winds from the Levant with the other four spices of panch phoron. Merchants from Java brought cloves and nutmeg, from the Malabar coast of south India came black pepper, turmeric, cardamoms and cinnamon. Ginger was delivered on junks from China and the Portuguese introduced chillies from the Americas. All these cosmopolitan flavours have been combined to create one of the most interesting and least exported regional cuisines of India.

Our introduction to the pleasures of Bengali cooking came from the kitchens of our hotel. We ate feasts of fish dishes made with local favourites hilsa and bhekti and giant prawns cooked in coconut milk, creamy dhals, and spicy vegetables. Keen to find other venues to taste more we began asking around.

One of the most endearing qualities of Bengali people is their enthusiasm for conversation with strangers. Even on our tours of Calcutta's tourist sites we had been made welcome. We had chatted to commuters in the streets around the faded imperial splendours of Dalhousie Square, among the passionate Hindu worshippers engaged in devotional sacrifice of Kali Ghat and with shy lovers sitting on the manicured lawns in the tranquillity of the city parks.

The great hub of Bengali chat is the Coffee House in College Street. The sign behind the counter, which asks patrons not to linger after consuming their beverage and to please observe silence, must be one of the most overtly ignored requests in the world.

The heroes of Bengal are poets, philosophers, novelists, political ideologists, film-makers, artists and musicians. They and their work are popular topics of conversation in the Coffee House, and so is the attempt by the government to change Calcutta's name to Kolkata. We heard no enthusiasm for this proposal. There was plenty of enthusiasm for talk about food, though. We gathered that until the smarter hotels started offering Bengali menus there had only been one restaurant in Calcutta offering traditional fare, a place called Suruchi's in Elliot Road. However, more were opening, and the most highly recommended, called Kewpie's, was hidden down a side street but not impossible to find. We asked if the driver who was to collect us the following morning for a tour of the city's markets would be able to drop us there at the end of the day.

Raju had turned up just before dawn. We were starting at the fish market and wanted to see it at its most frenetic as the fresh deliveries from the night were snapped up by eager cooks. The market was alive with fish and barter. Monster rohu and bhekti lay glistening on slabs, baskets of hilsa shimmered pink and silver, orange mango fish looked good enough to eat immediately and crayfish made hopeless bids for freedom. The daily demand for fresh fish is so great that much of it is farmed in huge ponds on the outskirts of the city and trucked in every night.

As the sun rose we pulled into the Armenian Ghat flower market. The riot of colour and soft fragrant petals made a welcome antidote to the smells and slime of the neon-lit fish market. It was a photographer's paradise, with hundreds of garlands of bright yellow marigolds, jasmine, frangipani and ylang ylang all piled up along the banks of the Hooghly River where people were busy attending to their morning ablutions. Above, the extraordinary cantilevered Howrah Bridge stretched over the river like a giant Meccano set. A policeman pointed out a sign forbidding photographs. When we asked him why, he said it was "in case they fell into enemy hands".

At New Market we found the ingredients for panch phoron in the spice bazaar. Here, a long line of spice merchants squat in tiny raised stalls down a narrow alley of such vivid colours and aromas it rivals the flower market in sensory pleasure. Phoron is the name for a seasoning added to dishes. The panch version is just one of many. The merchants will mix spices to the individual taste of their customers, then the plastic bags are sealed with a candle and handed over.

After lunch Raju drove us in his newly washed cab over Howrah Bridge and down to the Botanical Gardens where Bengali girls in bright saris played badminton in the dappled sunlight. They looked like butterflies flitting about after the shuttlecock. We took a boat up river to meet Raju back in town, and in the half-light of dusk a dolphin surfaced right next to us and blew water. Calcutta didn't really seem a bad place at all.

Kewpie's was the perfect climax to our visit. The food was all Bengali, plentiful, home-cooked and utterly delicious. The restaurant so friendly and casual we felt we were guests in a Calcutta family kitchen. Thank goodness we'd managed to work up an appetite since lunch.

'The Spice Routes', by Chris and Carolyn Caldicott, was published yesterday by Frances Lincoln (£20). Chris travelled to Calcutta with Cox and Kings (020-7873 5006), which organised the tour of the city markets and now includes a visit to Kewpie's as an option for guests

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