How Does Too Much Oil in Indian Mughlai Food Makes It Tasty? What is the explanation of oily food being tasty? How does extra oil enhances taste? 

It is evident  North Indian food specialy Mughlai food uses too much oil and it is also true too much oil makes the food tasty (at least to a large amount of people).

In a forum  one said that  lots of oil which makes dish look complete and well decorate. Even when fish is rich in oil they cook with extra oil to gives spicy taste. But I could not comprehend what he said. I want to know why taste is enhanced.

Could anyone please explain elaborately? 

Thanks!

Edit:


There's a book on this: Salt Sugar Fat: How the Food Giants Hooked Us  by
Michael Moss (Author). Oil doesn't improve taste much, but it improves "mouth feel". Imagine you substitute oil with water in peanut butter (google for "PB2"), or mash potato without butter. 
Harold McGee’s “On Food and Cooking”, use the index to find key topics.
Oil is a great non-polar solvent and will dissolve many flavor molecules that don't dissolve well in water.  “Like dissolves like”.  For instance, capsaicins from chili peppers, zingerone from ginger, piperine from black pepper, and many others, dissolve sparingly in water but well in oils.

Not just hot flavors, either - limonene (citrus), carvone (S and R forms, from spearmint and caraway), and other essences are non-polar.

Once dissolved, they're mobile and easier to taste.