. >> the c city marketing cape to. before the pandemic,c, it dre 7000 visitors a day.w just 700, and they are only allowed to buy essentials under stririct procedures. >> what i am doing g today, everybody who comes to the market, i take their n name, cel phone numbers, explainin why i m doing this, trtracking and tracg of covid. >> shoppers a appear happppy to cooperate. >> i i am c comfortable. i understand why they are doing it, but i knonow that it is keeping me safe and other peoeoe by n not spreading the virus. correspondent: if there is a case of coronavirus in the market, they can warn othehers o may be affected. by collecting names and contatat details, it is an easysy way to make contact tcingng possiblble, but not the most effective. universityty of cape t town researchers say a mobile app would make things s easier and more effective. he has overseen the development of the mobile app. every participanant can register online and then receiveve a qr code. this can be saved to the smarartphone or printed out as fewer than half of south africans own a smartphon