If Im not mistaken, Delhi's hottest month isn't in peak summer but in May and June, so now. As the climate is largly influenced by the monsoon season.
Next year also doesn't necessarily need to be worse, now going from an el niño into a la niña makes that somewhat unlikely, although regional differences will probably make some places worse, compared to this year.
Please correct me if I'm wrong, but people may be already dying by the thousands. Isn't it rather difficult for a doctor to point down the reason of death to heat?
If not next year, it will get worse rather quick, that's for sure. Much, much worse.