Solution:
In the first blank, article "the" will be used because a specific demonstration is being talked about. In the second blank, "no article" will be used because India is the name of a country.

Solution:
No article is required.

Solution:
No article is required.

Solution:
The first and second blank shall take 'the' as the sentence talks about a class of people (great) and their lives. The third blank won't take an article as 'contagion' is an abstract noun.

Solution:
In the first blank, the speaker is mentioning "fog" of a 'specific day', hence article "the" will be used. Similarly, in the second and third blank, the speaker is mentioning the definite side and road respectively, hence article "the" will be used.

Solution:
In the first blank, article "the" will be used because article "the" is used to refer to a definite time (afternoon). In the second blank, article "the" will be used because the speaker is specifically mentioning the 'afternoon wind'. In the third blank, "the" will not be used because the word "difficulties" has been used generally and not specifically, describing the type of it. The articles A and An can't be used because 'difficulties' is plural. So, 'no article'.

Solution:
All the three blanks shall take 'the' as the sentence talks about two particular person's state at a particular time.