Mumbai-He was lobbying with the UK government to change its stringent visa norms, which he termed as a big mistake said Mayor of London Sadiq Khan.He arrived in Mumbai on a official tour to three Indian cities, others being Delhi and Amritsar, to strengthen the UK capital’s trade ties.Theresa May government visa policy which came into effect in November will affect a large number of Indians, especially IT professionals. India last month flagged its serious concerns to Britain over its stringent visa norms and hike in threshold limit of annual pay of working professionals to get the travel documents.