Why is star delta starter preferred with an induction motor?

The main purpose of any starter is to reduce the requirement of high starting current.If one consumer has an induction motor with a DOL starter, drawing a high current from the line, which is higher than the current for which this line is designed. This will cause a drop (dip) in the
voltage, all along the line, both for the consumers between the substation and this consumer, and those, who are in the line after this consumer.This is the reason for which a starter is to be used.
In a (squirrel) cage induction motor, the starter is used only to decrease the input voltage to the motor so as to decrease the starting current.
 The starting current is reduced to approximately two-thirds. Since starting current is reduced , the voltage drops during the starting of motor in systems are reduced.