Kautilya's Arthashastra 13.4.24

13.4.24

kṣīṇanicayaṃ cāvāptam api rājyaṃ kṣayāyaiva bhavati // (iti paryupāsanakarma)

When a fort can be captured by other means, no attempt should be made to set fire to it; for fire cannot be trusted; it not only offends gods, but also destroys the people, grains, cattle, gold, raw materials and the like. Also the acquisition of a fort with its property all destroyed is a source of further loss. Such is the aspect of a siege.