Vodafone, Airtel prepaid plans with 84 day validity period; See full details here
Prepaid Plans: If you are looking for a prepaid plan with long validity period, then you have various options on this in market. All telecom companies have launched plans that will suit your requirements. You can take plans with 84 day validity period. You will get daily data, voice calls and other benefits
Airtel Rs 598 plan:Validity of this plan is 84 days. You will get 1.5 GB data on a daily basis. Which means you will get 142 GB data in 84 days. Source: PTI