"Impact on the tobacco industry is going to be largely neutral since the 5% cess declared by the Indian government was less than the expected rate by the tobacco industry. There will be an increase in the expense of smokers due to the rise in the price of a cigarette in the initial period. Although, it is expected that the tobacco industry, irrespective of the tax rate, would have a neutral effect due to the implementation of GST."
https://www.thehindu.com/opinion/op-ed/low-tobacco-tax-poor-...
"The lack of tax increases in post-GST years might mean that some current smokers smoke more now and some non-smokers have started smoking. This could potentially lead to a reversal of the declining trend in prevalence. This might jeopardise India’s commitment to achieving 30% tobacco use prevalence reduction by 2025 as envisaged in the National Health Policy of 2017 by the Government of India."
https://www.caclubindia.com/articles/taxation-and-impact-of-...
this one has more meat into it.
But neither one really shows that the prevalence of smokers pre- and post-tax hasn't changed.
In terms of numbers I can only find the 2016-2017 GATS numbers of 28.6% users, 10.7% smokers.
Ok, I think we'll need a quote for that. Various sources indicate falling percentage of smokers in recent years.