Kolkata is a city of contrasts when it comes to how people consume information. Salt Lake’s IT professionals live on apps and email, while Burrabazar’s wholesale traders and North Kolkata’s family-run businesses still trust a phone ringing or a text landing in their inbox far more than a push notification they can swipe away. That split matters for any business trying to reach customers reliably, and it’s exactly why SMS, an unglamorous channel that predates smartphones, continues to outperform flashier alternatives across this city.
Why Email and App Notifications Fall Short Here
Email open rates in India hover in the low double digits for most industries, and that number drops further once promotional folders and spam filters are factored in. App notifications depend on the customer having installed your app and left notifications turned on — a shrinking assumption as people trim the apps on their phones. SMS sidesteps both problems. It doesn’t need an internet connection to arrive, it doesn’t get buried in a folder, and it doesn’t require an app install. For a city with as much network variability as Kolkata, particularly outside the core IT corridors, that reliability is often the difference between a customer knowing about an offer and never hearing about it at all.
Language Is Where Most SMS Campaigns Quietly Fail
A large share of Kolkata’s retail and healthcare customers respond far better to Bengali communication than to English. Yet many bulk messaging platforms built for a pan-India audience treat Bengali as an afterthought, and the result is messages that arrive as broken symbols instead of readable text. A jewellery store sending a Durga Puja offer, or a diagnostic centre confirming a lab appointment, loses the entire point of the message if the recipient can’t read it. Getting Bengali Unicode encoding right isn’t a nice-to-have feature; for a meaningful slice of this market, it’s the deciding factor in whether a campaign gets a response at all.
The Festival Calendar Changes Everything
Few Indian cities have a commercial calendar as concentrated as Kolkata’s. Durga Puja alone drives a spending season worth tens of thousands of crores, and retail, food delivery, and e-commerce businesses routinely see promotional SMS volumes jump three to four times their normal levels in the weeks leading up to it. Businesses that don’t plan ahead for this surge often discover the hard way that shared messaging routes get congested exactly when they need them most, and a campaign meant to reach fifty thousand customers ends up reaching a fraction of that. Planning capacity in advance of Puja, Kali Puja, and Poila Boishakh isn’t excessive caution here; it’s simply matching the infrastructure to how the city actually shops.
BSNL Coverage Still Matters More Than People Assume
It’s easy to assume every customer in India is on Jio or Airtel by now, but that assumption doesn’t hold in older, established parts of Kolkata. Burrabazar and much of North Kolkata still carry a meaningful base of BSNL subscribers among long-running businesses, and providers that only route through private operators quietly leave those customers unreached. A campaign that looks successful on paper can still be missing a real segment of the intended audience if the routing doesn’t account for every operator active in the region.
Time-Critical Messages Need Their Own Lane
Not every message can wait in the same queue as a festival promotion. Login codes, payment confirmations, and delivery alerts fall under transactional SMS, which needs to reach both DND and non-DND numbers within seconds, at any hour. Fintech apps, hospitals, and e-commerce platforms operating in Kolkata depend on this distinction, and providers that mix transactional traffic with promotional traffic on the same route tend to see delays exactly when speed matters most. OTP delivery in particular needs a dedicated, priority route, since a customer abandoning a transaction because a code arrived late is a lost sale, not just a technical hiccup.
