Generally, when heat is given to the enclosed air, both volume and pressure undergo changes i.e., pressure of the air increases with increase in temperature keeping volume as a constant and vice versa. As it is an enclosed substance where pressure of the air increasing, the substance will burst in order to escape the excess of the pressure.
Similarly, during summer, when the surrounding environment is hot, the air inside the tyre of a vehicle (such as car, bicycle, lorry, bus and much more) will get heated up with the increase in pressure of the air inside the tyre. As there is no place to air to escape tyre will get bursted. Hence, during summer season, air in the tyre should not be completely filled up and need to maintain the threshold limit of the air in tyres of the vehicles to keep it safe.