The limit is 1500 but I have 1604. It's an international school and they don't have an email address for questions- I'm having difficulty calling them from overseas.
I think you should just cut down the words. I know it seems impossible, but read the essay aloud. I had to cut my 600 word UC essay down to 500 words, it takes a couple reads, but you will find places you can combine words and phrase things differently.
You should always keep your essays under or at the limit. It shows that you can tell your stories succintly and that you are able to think your ideas through. Also, it's a good idea to show that you can follow directions.
The word limit is part of the essay. It shows how well you can express yourself in a limited space. If you miss the limit miss it on the low side not the high side.
If you aren't writing in your native language it is more difficult to write inside limits. Get help from someone you know and trust in your field if you can. The vocabulary and word usage at the graduate level are different for every field.
Most give non native speakers more latitude but it is best to get it right.