For each gas station there are the fuel prices, e how many days ago they were entered.
For some gas stations, the fuel prices have not updated since long time, and so the indication has become useless and misleading. It may be that it's listed an expensive price for a gas station just because in the past the fuel was everywhere more expensive than now (and hence now nobody will go to that gas station, and the prices of that station will not get updated anymore).

Hence, my proposal is that, after some time (say, two months), the fuel prices are discarded