This was what I got:
I wished I've read this website earlier - www.cloudsorchids.com/doctor/dleaf.htm
The problem I'm facing can be found under the "Leaf Yellowing - Cultural section" - If little puddles of water sit on leaves for long periods of time, then the leaf will usually turn yellow, then brown and finally black. This is because the leaf cells in that area have died. Always ensure that your plants are completely dry before nightfall. Be especially careful of small depressions in leaf surfaces that can trap water.
I had to cut off about 12 leaves from my beautiful orchid plant. It now looks like it had a really awful "haircut"!
My orchid plant in its beautiful days
I love how the flowers last such a long time