Question: when was the name of calcutta changed to kolkata
[{'answer': '2001', 'provenance': [{'wikipedia_id': '850010', 'title': 'Renaming of cities in India', 'start_paragraph_id': 11, 'start_character': 282, 'end_paragraph_id': 11, 'end_character': 286, 'bleu_score': 1.0, 'section': 'Section::::Renaming in English.:Realignment of the official Indian English name to an alternative local name.\n'}]}]