To taste tandoori chai, you may need to go to Pune or one of the highways stretching out of it. It’s made by taking iron tongs to place an earthen cup in a glowing hot tandoor (or just a large metal drum).

When the cup is super-hot, it’s taken out and sweet milky chai is poured in, which sizzles and froths over. Then this chai is poured into another kulhad and served. The process gives it smoky, earthy notes, with perhaps, some caramelisation from the sugar. Its pleasantly, if not vastly, different and makes for an entertaining show.

The Pune connection comes from Amol Rajdeo, who runs the Chai La tea shop there and says he was inspired from watching his grandmother place a kulhad of turmeric milk in the corner of a bonfire to heat it. And from Pune the idea seems to have been picked up by chai makers on the roads leading out.

I’ve noticed the tandoori chai signs spreading away from Pune and first tried it myself in Ajara, a small town that makes for a convenient break on the Pune to Goa road. It has reached the outskirts of Mumbai, with reports of tandoori chai in Navi Mumbai and Panvel, and might be within the city soon.

Or maybe not. Tandoori chai could be like ‘market’, a once trendy option in Mumbai’s Irani restaurants which consisted of milky coffee mixed with milky chai. The mysterious ‘market’ name was explained by Rashid Irani, the film critic who also used to run the Baghdadi café, when he told me that it came from the slang the servers used to call for it from the kitchen: ek coffee mar ke chai!

You won’t find it today and no surprise, since it’s not exceptional, with coffee and tea flavours cancelling each other out and everything drowning in milky sweetness. But it shows how there’s always a market for innovative new products to taste, and this innovation isn’t just driven from abroad.

For every sickly sweet pumpkin spice latte put forth by international chains, you have a tandoori chai invented from within India and spread along the highways, which have always been a great route to disseminate food products. Bored families on long drives and weary bus passengers are always happy for a distraction, if it isn’t too expensive and, now, gives them something cool to film on their phones and put on social media.

Chai itself was once a trend that developed this way. A century back, as the Great War ended, British tea growers in India found themselves with a surplus of cheap tea that was grown for war supply. They decided to step up efforts, minor till then, to sell tea drinking to Indians.

But the great tea promotion campaign they launched didn’t seem able to persuade Indians to drink the bitter beverage — until unknown Indian tea makers started mixing it with lots of milk and sugar, creating chai, the tea trend that Indians would really adopt.