Kenya picked a Chinese firm for a $2.9 billion upgrade of its biggest airport, people with knowledge of the matter said, two years after a concession deal with Indian conglomerate Adani Group was cancelled.The East African nation awarded China Communications Construction Co. an engineering, procurement and construction contract to update and expand the Jomo Kenyatta International Airport, the people said asking not to be identified as they are not authorised to discuss the matter.The deal cements Chinese companies' grip on major infrastructure projects in Kenya, where CCCC's portfolio already includes a new railway, a 60,000-seat stadium, a toll road and a convention centre.