Assertion:  The emergence of the Mewar School is widely associated with an early-dated set of Ragamala paintings painted at Chawand in 1605 by an artist named Nisardin.
Reason:  Long wars with the Mughals have wiped out most early examples of Mewar School.

Both the Assertion and the Reason are correct and the Reason is the correct explanation of the Assertion.

Mewar is conjectured to be a significant early centre of painting in Rajasthan, from where, hypothetically, one would have been able to formalise a continuous stylistic tradition of painting — from pre-seventeenth century bold, indigenous styles to the subsequent refined and finer style post Karan Singh’s contact with the Mughals. However, long wars with the Mughals have wiped out most early examples. Therefore, the emergence of the Mewar School is widely associated with an early dated set of Ragamala paintings painted at Chawand in 1605 by an artist named Nisardin. The set has a colophon page that reveals the above vital information. This set shares its visual aesthetics and has close affinity with the pre-seventeenth century painting style in its direct approach, simpler compositions, sporadic decorative details and vibrant colours.