Airtel must launch a plan with monthly rental of 60 rupees for 28 days and give 20 rupees talktime and charge just 30paise/min. Free data of 500MB or 200MB can be given. If this is done, many low usage people will go to Airtel. When Jio started in 2017, if Airtel charged 30paise/min, this wont work for Airtel because they were not charging 45 per 28 days. If no minimum monthly pay is there, Airtel would get just 6 rupees per month for a user who talks 20 min per month. Now that they charge 45 or 49 per 28 days, they can get 51 rupees/month. If 45 is not enough for 28 days, Airtel can introduce, say, 60 rupee rental with 30paise tariff. The 30paise if for other network. They can charge 10 or 15 paise for Airtel calls. If Airtel introduces such a plan, Jio will have huge subscriber losses and many users will go to Airtel (even if those people are low volume users)
