Hmm kind of blends with the colour. Have to try moving a bit away from the merlion he he. I was 18mm, no zoom. but then again have to crop as there is no scenery from where I stand. As I said have to move away from the merlion ;p
nope, try using burn 3-5%(my personally setting) and set it to midtones and do some slight burn on the more obvious smoke before changing it to shadows and burn again. but like i say, poor or too much burning might make it looks weird.
another way is like what Dan have said, use U-point from Nikon capture NX. great tools
Of course result depends on yourself
1.Go to select color range, click the black sky & push slider to extreme right.
2. Now you MAY want to use curves to darken the overall sky.
3. Now paint back/mask parts where smoke is necessarty especially lower parts where sky meets water.
actually its because his shutter speed is slow, that's why even the not very bright smoke can be picked up by the camera...
one easy way to reduce smoke is simply, in levels, push the black level to the right...this would reduce the smoke...but don't push too much or the image becomes too dark...and like others have mentioned a bit of smoke makes it more real...