 Sewage fed aquaculture based artificial wetland, like East Kolkata Wetland (EKW), is a robust example of potential carbon sink and spin-off.EKW can sequester ~1.9 Mg C/ha/year, mitigating at least ~118 Gg atmospheric CO2/year.Plus, carbon uptake by harvested fish crop corresponds to ~61 Gg CO2/year - rewarding USD 3.6/kg blue C harvested.