Hi Abhijeet, do you think that we could reorganise the structure of the article a little? Below is a slightly altered structure.
There are two places that the article seems to contradict itself... I may be wrong.
- " Trash in a landfill doesn’t break down as there is little oxygen or moisture inside. This calls for constant monitoring and maintenance of landfill for at least 30 years." and then, almost immedistely after "Landfills can be very harmful both for the human health and environment. This is because food waste buried inside landfills decompose easily for lack of contact with sun or air."
- "Methane is lighter than air and collects at the top of enclosed spaces". and then shortly after "Once it enters buildings, it gets trapped in the lower parts of a building"
 This is the structure that I thought may help.
- What are Sanitary Landfills? 
- Why are landfills used?
- What makes a landfills a sanitary landfill?
- What are the other types of landfills?
- How does a Sanitary Landfill work?
- What are the hazards of using Sanitary Landfills?
- Management of leachate? (do include what a leachate is)
- Electronic waste in landfills.
- Waste disposal concerns
- What are the benefits of sanitary landfills?
- Landfill gas
- Hazards of landfill gas
- Considerations to keep in mind when setting up a Sanitary Landfill
- Site selection
- Engineering- explain what a "cell" is.
- What are the alternative solid waste disposal techniques?
- What can I do
- Composting and other household alternatives