(S (S (S (BASENP (DT A) (NN search) (NN operation)) (VP (VBD was) (VP (VBN launched) (PP (IN by) (BASENP (DT the) (NNP Indian) (NNP National) (NNP Disaster) (NNP Response) (NNP Force)))))) (CONJP (COMMA ,) (CC but)) (S (BASENP (NNS efforts)) (VP (VBD were) (VP (VBN hampered) (PP (IN by) (BASENP (NN nightfall))))))) (PERIOD .))