Valve ea polasetiki ke mofuta o sebelisoang haholo oa li-valve, o na le melemo ea ho hanyetsa kutu, boima bo bobebe, ho hanyetsa ho roala, joalo-joalo E sebelisoa haholo lik'hemik'hale, petrochemical, ts'ireletso ea tikoloho le liindasteri tse ling.Se latelang ke histori ea tsoelo-pele ea li-valve tsa polasetiki.Lilemong tsa bo-1950, ...
Bala haholoanyane