Sarg means Creation and Pratisarg means destruction of Creation (Pralaya).

Cosmogony - the theory of creation and dissolution. The ancient Hindu, around 3000 BC gave a lot of consideration to the question of origin of the Universe and came to the conclusion, that it was impossible for any man to give the definite answer to this question as how the Universe was created and when, and what was the ultimate end of Creation. Hymn 10-129 of Rig Ved, known as Naasdeeya Sookt reflects a high degree of maturity of thought by categorically denying to answer the above questions of Creation. It states that God created the Universe. Did He have the elemental material from which He built it, or did He first make the elemental material?

To this, the Sookt answers that only the Creator can answer this - no one else, because even Devtaa came later. This is as bold and as honest a statement as ever made by seers of any religion. It contrasts with the simplistic Christian statement that God created the world in six days and needed rest on the 7th day. How could have been a division of days and nights when there was no Sun?

Manu Smriti, written in 3rd century BC, says the same as Rig Ved stating that it was impossible to say how and when the Universe was created? [Manu Smriti, 1-5, 1-6, and 1-57]

Upanishad on Sarg
Upanishad touch this subject only peripherally.
--Chhaandogya Upanishad [6-2-1] states that "in the beginning, there was "Being" alone. He thought, "Let me become many", let me grow forth.
--Mundak Upanishad [1-1-7] states that "as the web is spun off the spider, as trees spring from the Earth, and the hair from the body; so has the Universe sprung from God eternal."
--Shwetaashwatar Upanishad [1-1] begins by asking questions on the subject, "How did the Universe come into being? Did God create it? Who created us and why? Where are we going from here?" It indirectly answers in the next verse that the Creation of the Universe was not a chance phenomenon. It came by the design of Almighty.

Puraans on Sarg
Upanishad were followed by the Puraan (250-1050AD). The Puraan normally deal with five topics - (1) Sarg - Creation, (2) Pratisarg - Pralaya or Dissolution, (3) Manvantar - Eons, (4) Genealogies of kings and seers, and (5) Life sketches of notable persons. The Puraan built their own theory of Creation and Dissolution. They defined a period of 4,320,000 solar years as a Kalp. The Universe exists for 2,160,000 years (the day of Brahmaa) and then disappears for the same number of years (the night of Brahmaa).

Each Kalp is divided into 14 Manvantars (Manu-Antars). At the end of the each Manvantar, human race is completely destroyed. The new Manvantar starts with a new Manu. In Christianity, only 2 Manvantars are recognized. The first one was started by Adam (corrupt of Aadi Manu), and the second one was started by Noah (from Aramaic Nooh, which is also the corrupt of Manu). They also created statements and stories for the measurement of time relating to Creation and Dissolution.

By accident, they seemed to have come to a time-period, which looks more reasonable for the Creation of the Universe than the one mentioned in the scriptural texts of the Semitic religions. See Lok. The Jains believe that God did not create the Universe. The Universe was always there.
[Aangiras, p 381-383]