My lemons are cracking as shown in below image:
What can be causing this and how can I prevent this in the future?
Location: India. Weather In May-June: Hot! > 95F days.
According to http://ceventura.ucdavis.edu/Gardening/Coastal/Veg-Fruit/CitrusCrack/ it is due to uneven watering... Which you sometimes just can't avoid in containers... So you could step up to a larger container or add some sort of inverted bottle drip system...
I don't have a lot of citrus experience, but with other fruit, sometimes just too much direct sun can cause the water to expand and break the fruit open.
So I guess the answer is too much turgor pressure... The cause being osmotic pressure from sporadic watering or expansion pressure from over heating.