We should use coal and petroleum judiciously. Why ? State any four reasons

(i) Reserves of coal and petroleum are limited.
(ii) Combustion pollutes the air forming oxides of C, H, N, S.
(iii) CO is formed instead of C$O_{2}$ if there is insufficient air.
(iv) Oxides of S, N and CO are poisonous.
(v) C$O_{2}$ is greenhouse gas that leads to global warming.