Constraining CSL strength parameter $\lambda$ from standard cosmology
  and spectral distortions of CMBR
  Models of spontaneous wave function collapse modify the linear
Schr\"{o}dinger equation of standard Quantum Mechanics by adding stochastic
non-linear terms to it. The aim of such models is to describe the quantum
(linear) nature of microsystems along with the classical nature (violation of
superposition principle) of macroscopic ones. The addition of such non-linear
terms in the Schr\"{o}dinger equation leads to non-conservation of energy of
the system under consideration. Thus, a striking feature of collapse models is
to heat non-relativistic particles with a constant rate. If such a process is
physical, then it has the ability to perturb the well-understood thermal
history of the universe. In this article we will try to investigate the impacts
of such heating terms on standard evolution of non-relativistic matter and on
the formation of CMBR. We will use the CSL model, the most widely used collapse
model. We will also put constraints on the CSL collapse rate $\lambda$ by
considering that the standard evolution of non-relativistic matter is not
hampered and the observed precise blackbody spectrum of CMBR would not get
distorted (in the form of $\mu-$type and $y-$type distortions) so as to violate
the observed bounds.
