Voting is underway in Burundi presidential election, amid unrest over incumbent President Pierre Nkuruniziza's bid for a third term in office. Fears have been rife that the polls may trigger violence. A grenade exploded in Bujumbura, the capital's central business district yesterday. For an update from Burundi's capital Bujumbura, Lulu Gaboo spoke to our coresspondent there Bernard Bankurira