Passage: The race in the arid northwestern India and Pakistan, dilutum, has pale yellow upperparts, a long crest and whiter underparts than the nominate race of the Gangetic plains. The upperparts have less spots. They prefer to breed in old gnarled tamarisks, Acacia and Dalbergia trunks. The nominate populations is found across India in the low elevations up to about 1000 m.

Question: Up to what elevation are the low lying populations found?
1000 m