Direct questions vs. Indirect questions

Direct Question 

1: What is your favourite TV program? 

Vs. 

Indirect Question 

2: I would like to know what your favourite TV program is. 

Tell me why there is so much pollution in the world. 

Do you know where we can buy the best ice-cream? 

Can you explain how we should prepare for an interview? 

Affirmative word order:   This is your favourite TV program.

Interrogative word order: Is this your favourite TV program? 

Do you know the word order in a question compared to the word order in an affirmative sentence? 

Do we use the word order of questions or the normal affirmative sentences here in the indirect questions? 

Is there an introductory phrase before the question word in the indirect question?