We have just returned from the worst imaginable cruise possible. We expected to go on a cruise of Dubai and the Jewels of the Emirates. On arrival at the Costa reception desk in Dubai we were handed a letter stating that minor works were in progress on the ship with minimal disruption. What a farce. Much of the atriums on the 4th and 5th deck levels were cordoned off and also a major area at the side of the grand bar on deck 5. Major building works started from about 7.30 am throughout the day and into the early evening. The noise was horrendous with the noise of hammer drills, kango's, angle grinders and arc welders in continuous use. Our cabin was directly above major works on the 5th deck atrium. The continual noise coming up through the floor made it impossible to stay in our room at any time during the day. My wife suffered from headaches and a migraine and I had quite a few coughing bouts due to being asthmatic which made my condition far worse than normal. Also there was constant stenches from solvents and burning of metal caused by angle grinders. The builders and some staff were wearing protective dust masks at various times, but no consideration was given to any of the passengers. It was a relief when the cruise finished and we were heading back to the airport. This ship should have been taken out of service and put in dry dock to carry out the extent of the modification required.