TATA Motors Indigo Owner's Manual & Service Book - page 119
of
164
117
MAINTENANCE & CAR CARE - Carbon Canister
CARBON CANISTER (Petrol Engine) :
As petrol evaporates in the fuel tank, hydrocarbons are discharged
into the atmosphere. The carbon canister stores these hydrocarbons
from the fuel tank.
Air drawn through the carbon canister into the engine should be
controlled to maintain exhaust emissions within desired limits as
well as to ensure good driveability.
The carbon canister should be replaced at an Authorised Service
outlet.