Mumbai, Aug 25 (ANI): RJD Chief and former Bihar Chief Minister Lalu Prasad Yadav was rushed to a Mumbai hospital after he was taken ill on Monday morning. According to reports, Yadav will undergo heart valve replacement surgery. Two of his valves need replacement. Lalu's RJD and Nitish Kumar's JD (U) have come together to contest the by-polls in Bihar. It is a crucial day for the RJD Chief as results for the by poll elections on 10 seats of Bihar will be out today.