Here are some of the answer to your questions on drones.
Which is the First Drone ?
If you are referring to the commercial use of UAV then those drones were invented in 1980s. Prior to that scientifically drones originate back in 1849 as first UAV (Unmanned aerial vehicle). Today the UAV you see as commercial use for taking images and weather monitoring are referred to as drone. Also the military calls them drone for their unmanned attacks. Scientist prefer the term UAV.
Where was it invented and by whom?
First UAV was invented to attack venice by Austria, in 1849. From 1915 onwards their use in combat was too regular in regions which were hard to infiltrate
How many Drones does India have?
Publicly released drones of the Indian military or science department can be listed on their respective website. Or you can read the Wikipedia.
You can also track commercial drones in the market by checking the license holders data. However not all of them are registered so it's hard to get the accurate data on this.
Are there Drones that detect the fuel after burning or Combustion or detect the smoke in the sky? Has it been invented ? If yes by whom ?
There are some photosensors and some specific gas sensors that can be enabled on drones. However the accuracy of such sensors stops from proper detection of "detecting if the content is fuel or any other substance". Smoke can be easily confirmed with photosensors and imagery along with gas sensors. No specific data on who has invented is available on the internet. However you can find commercial sensors on gas leakage and smoke detection easily. Integrating such components on drone isn't hard on commercial or military scale.
What does Drones include?
What drones include depends on the application of the drone. For example commercial toy drones are just calibrated motors and fan that can be managed with the joystick. As for the military level drone may include imagery (camera and satellite connection) and detection sensors.
Does Drones include Computer programming language or Computer Graphics, Grid Computing or What type of computing is been used ?
Based on the data available on the internet. Drones can be programmed to follow specific path. The type of programming language for them depends on the manufacturers specification. Some of the articles from wiki refers to the drones making use of raspberry pi and can make use of python, java and nodejs.
You can search for "Drone Pi" to know more about the type of language you can use and the type of computing that is possible in such drones. More advanced drones underlying technology is harder to find out since such data is not public unless the commercial application is visible.
Is there Maths included in the Drones to identify the location?
Location detection options are possible with satellite connectivity which may be costlier. Or GPS can be integrated for location information. Depending on the price the reasonable component can be integrated.
Will there be Artificial Intelligence inside the Drone or Drones been operated from the remote location ?
AI related changes in the drones are limited to the military and government drones. Commercial drones making use of AI is likely to be restricted and put under some policy. That's why normal citizen can't use drone from X country to take pictures in Y country from remote location. And so such usage is for military use only. Limits of operation and the amount of distance traveled from location of release may depend on the drone components. Some only travel specific distance without any connection from the sender. So in terms of AI, that development is limited to the government and the military.