THOMAS MUKOYA STYLIST Julia Wanja picks her way delicately through piles of food waste, discarded masks, rubber gloves and other rubbish at Nairobi's Dandora dumpsite, looking for used hair extensions she can clean and resell to customers. The pandemic means fewer clients with less money and she is cutting down on costs by cleaning and reselling hair from the dumpsite. Officials direct trucks to dump their loads depending on where the waste has come from. Domestic and commercial waste - which includes bags of hair extensions discarded by other salons - goes to different sections. Medical waste is usually incinerated.…