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We don't have any transformations for Everest 1830 because it's a ellipsoid (spheroid) and not a true geodetic datum/coordinate system. The data may be using Kalianpur 1937. Take a look at the geographic_transformations.pdf file located in your ArcGIS installation's Documentation folder for GCS that are used in India (or wherever the data is) and try some of them. It will mean redefining the Everest 1830 data with the Define Projection tool or the data's property page in ArcCatalog.