Genting Hong Kong is paying EUR 69.1m ($81m) to fit scrubbers on three of its cruiseships.
The company said Estonia's LTH-Baas will work on the 75,000-gt Superstar Virgo (built 1999) and the 151,000-gt Genting Dream (built 2016) and World Dream (built 2017).
The exhaust cleaning systems are expected to be fitted by 2020.
Genting has also contracted UAE company UMOS at a cost of EUR 7.7m