NEW DELHI: The Centre's new guidelines governing taxi operators across the country will allow aggregators such as Ola and Uber to charge up to three times the minimum fare during the day and up to four times between midnight and 5 am.The minimum fare will have to be submitted to the state transport departments for approval.The guidelines also allow private vehicles to be used as taxis by paying the required fees and getting their permissions online.Cabs with an All India Tourist Permit (AITP) will be allowed to operate under the aggregators. Such vehicles can also be engaged by BPOs, IT companies, government departments and PSUs for long-term hiring.The price regulation will cover only vehicles that are less than four metres in length, which have been categorised as "economy taxi".All taxis will have to comply with local fuel and other regulatory norms and have an app-based metering system that must be validated by an agency approved by the IT ministry.