To give you some idea of what they looked like earlier on, here's an older picture.

It looks like Sulphur deficiency. Have you been fertilizing?

I think the problem could be similar to that of your palm. Ficus benjamina is a tough plant and is hard to kill. It comes from a hot climate but normally grows in forest where there's high humidity. Roots are down in the cooler shaded soil of the forest with the leaves out in the blazing sun. But leaves going like yours could be from too much water. What is the soil like? Does it drain well?

Here when the rainy season comes and the soil becomes saturated the benjaminas lose a lot of leaves. Then they readjust to those conditions and grow normally. Rainwater has a lot of oxygen which the plant roots need. That's not usually the case with town water.

One thing to remember is that most benjaminas start off as epiphytes, their roots are exposed to air. So they don't like heavy soil unless they can run roots over top of it as in rainforests. So in general, I think you'd need to repot into a lighter fast draining soil and try to keep the roots in a cooler situation.

Thanks again for taking the time to reply. I really appreciate it. The soil perse doesn't seem to be draining all that well, meaning it takes quite a bit of watering for water to start draining out the bottom of the pot. I try and make up for that by watering the plant ever other day only and when I do, watering until it does run out the base. I'm fully with you about the roots being too hot theory, what with temperatures rising to 41 degrees a few days ago, but I do have a submission about the pot - it's being made of clay means that the ambient temperature will naturally be much cooler than a plastic or cement pot due to the constant evaporation of water. It's kind of like if you put water in an earthen pot for drinking water. Do you think supplementation with sulphur should be explored? Apparently Indian soils are notorious for their low sulphur content.

Here is a link that might be useful: Cooling drinking water using earthen pots

hoosierbanana,
thanks for replying. Actually it's been a while since I've fertilised this plant, in fact it's never been fertilised using actual chemical fertiliser. Around here we normally use organic compost as a fertiliser. Do you think that would be sufficient, or does it's current state warrent a specific sulphur-laden chemical fertiliser?