I am planning my holiday and I originally wanted to go Chiang Mai. However, after reading on the internet, I learnt that March is the worst time to to because of the smoky air. So, what are the alternatives of Chiang Mai that could allow me to take some landscape photos for my paining class?
Haze is an issue throughout Thailand (and the rest of mainland SE Asia) during March. It is the end of the long dry winter season, so dust is a big contributor. The long dry period also makes forests dry, so forest fires are also a big source. Plus the farmers are burning to prepare for planting rice and corn. It is not a good time of year for landscape photography anywhere, except maybe right on the coast where sea breezes might clear things up.
The northern provinces tend to get the most press because they are popular tourist areas, plus the surrounding mountains can trap the particulate matter when high pressure systems come through. But I was just in central Thailand and the haze there is enough to wash out photos.
But all that said, if a low pressure comes through bringing some rain and breezes, the air can clear out quite nicely, even in the mountain valleys.
If your primary goal is landscape photography, you might want to reschedule for November.