Purification of exhaust gases

In a process for purifying exhaust gases from an internal combustion engine being operated with a substantially stoichiometric fuel-to-air mixture, said exhaust gases containing hydrocarbons (C.sub.n H.sub.2n+2), carbon monoxide and nitric oxide and having an L-value of between about 0.8 and 1.2 where ##EQU5## and n is an integer, comprising the step of contacting said exhaust gases at an elevated temperature with a catalyst supported on a carrier which has been calcined at a temperature of at least about 800.degree. C, whereby said hydrocarbons, carbon monoxide and nitric oxide are simultaneously removed from said exhaust gases, the improvement comprising said catalyst essentially consisting of said carrier having distributed thereon a mixture from about 0.01 to 0.1% by weight each of molybdenum and rhodium and from 0 to about 0.1% by weight of platinum.