Question: what led to the end of india valley civilization
[{'answer': 'Aridification', 'provenance': [{'wikipedia_id': '46853', 'title': 'Indus Valley Civilisation', 'start_paragraph_id': 111, 'start_character': 0, 'end_paragraph_id': 111, 'end_character': 13, 'bleu_score': 1.0, 'section': 'Section::::Late Harappan.:Climate change and drought.\n'}]}, {'provenance': [{'wikipedia_id': '46853', 'title': 'Indus Valley Civilisation', 'start_paragraph_id': 2, 'start_character': 529, 'end_paragraph_id': 2, 'end_character': 799, 'bleu_score': 0.8698001842624911, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 2326029708702922378}, 'section': 'Section::::Abstract.'}]}]