1. What Does It Mean?
Summing up delimitation in a nutshell, the Election Commission of India website says that it is the "act or process of fixing limits or boundaries of territorial constituencies in a country or a province (state or UT) having a legislative body." The process may also entail a change in the number of Lok Sabha seats allotted to different states, as well as in the number of Legislative Assembly seats for each state.
Now, one of the important principles that the Constitution had called to be kept in mind for the delimitation exercise was the maintenance of a uniform population-seat ratio, meaning that number of people elected leaders are representing should be uniform within and between states across the country "so far as practicable".
However, maintaining that uniformity has proved to be a challenge, but, more on that later.