English.. Is it fine to say 43 lakh or 43 lakhs , what is the difference?

The word 'lakh' is not an English word. It is borrowed from Hindi (I believe). I don't know what the plural of 'lakh' is in Hindi but it is probably not 'lakhs'. When used in English (as an English word), it would normally follow the same rules as other numerical words where the use of the plural or not is a convention rather than any set rule. When talking about a definite (or sometimes an indefinite) number, one does NOT usually use the plural, for example: "Three hundred pounds", "Several million pounds" BUT if the word is used in a GENERAL sense (as an order of magnitude), then the plural is often used: "You can earn thousands of pounds a year", "There were hundreds of people in the crowd" A lakh is equal to 100,000 (for which there is no word in English but which, in words, would be pronounced "a hundred thousand"). If the amount stolen was 4,300,000 [rupees] this would be expressed as "four million three hundred thousand rupees" in English terminology or (following the same rules) "forty three lakh", however, Indian English is actually a different 'dialect' of English (as is American English) and the convention would seem to be to say "43 lakhs [of rupees]". See Merriam-Webster's definition here: http://www.merriam-webster.com/dictionary/lakh

I don't know if I could answer that as reading your topic I come up with a question myself; what does 'lakh' indicate? Does it indicate the Rs currency? Is it similar to saying, for instance, $100 dollars?

Though 'lakh' is not an English word, but we, the Indians' use it in English. As 43 is a pleural number, it would definitely be 43lakhs in stead of 43lakh. But modern English does not always follow grammar strictly. For example, the correct form is 'He is taller than I', but 'He is taller than me' is now mainly used and is treated as correct. So you can use whatever you like.

Yeah it should be lakhs. some people also write it like Lacs or Lac. I don't know which one is correct here. The editors are also humans and they did this mistake. ..Thanks for sharing and have a wonderful day ahead.