I don't know why we don't agree that marathas who weakened mughal empire. Lol. Maybe, if Indians are not part of this forum, we would have agreed I think.

Aurangzeb fought a 22 year battle with marathas and lost thousands of his men and marathas who were relentless in taking back the ports they lost. At the end Aurangzeb went back to Delhi as a broken old man and died leaving mughal rule in chaos.
Causes of the Mughal Decline
Before turning to these last
years of the Mughal empire, it may be
useful to summarize what appear to
have been certain general causes of
Mughal decline, leaving aside such
specific causes as external invasions
and internal rebellions. One feature of
Islamic power in India, as elsewhere,
was the failure to make progress in
certain vital fields. For example, even
Akbar failed to see the possibilities in
the introduction of printing. The
scarcity of books resulted in
comparative ignorance, low standards
of education, and limitation of the
subjects of study. Because of this, the
governing classes were ignorant of
the affairs of the outside world. The
position becomes clear if we [[274]]
compare the books on India printed in
Europe during the eighteenth century
with the knowledge of the West
current in India. The interest on the
part of Europeans that led travelers
like Bernier to make reports on their
travels finds no parallel in Mughal
India. So far from being concerned
with Europe, the Mughals, after Ain-i-
Akbari, made no real addition to their
knowledge even of their own
dominions.
The stagnation visible in the
intellectual field was visible also in the
military sphere. Babur had introduced
gunpowder in India, but after him
there was no advance in military
equipment, although the organization
and discipline of forces had been
completely revolutionized in the West.
The Portuguese had brought ships on
which cannons were mounted, and
had thus introduced a new element
which made them masters of the
Indian Ocean. What was a fortified
wall round the country became a
highway, and opened up the empire to
those countries which had not
remained stagnant. Mughal
helplessness on the sea was obvious
from the days of Akbar. Their ships
could not sail to Mecca without a
safe-conduct permit from the
Portuguese. Sir Thomas Roe had
warned Jahangir that if Prince Shah
Jahan as governor of Gujarat turned
the English out, "then he must expect
we would do our justice upon the
seas." The failure of the Mughals to
develop a powerful navy and control
the seas surrounding their dominions
was a direct cause of their
replacement by an European power
having these advantages.
On land no real progress or
large-scale training of local personnel
in the use of artillery was made in
Mughal India, and the best they could
do was to hire foreigners for manning
the artillery. The military weakness
resulting from this was obvious, and
was clearly visible to foreign
observers. Bernier wrote in the early
years of Aurangzeb's reign:" I could
never see these soldiers, destitute of
order, and marching with the
irregularity of a herd of animals,
without reflecting upon the ease with
which five-and-twenty thousand of
our veterans from the army in
Flanders, commanded by Prince
Condé or Marshal Turenne would
overcome these armies, however
numerous." /10/ With this condition of
the Mughal army, the downfall of the
empire was only a question of time.
[[275]] Another factor which
contributed to the fall of the Mughal
empire was the moral decay of the
ruling classes. This was partly due to
the affluent standard of living
maintained by monarchs like Shah
Jahan and queens like Nur Jahan.
Ostentatious luxury became the
ambition of everyone who could afford
it, and the puritanical Aurangzeb's
attempts to arrest the tide were
without success. The evil had gone
too far and was only driven
underground, to reappear within ten
years of the emperor's death, in the
uncontrolled orgies of his grandson
Jahandar Shah. Perhaps Aurangzeb's
extreme asceticism and self-denial
only intensified the reaction of the
nobility. Many a Maratha hill fortress
captured after long and dreary siege
was lost because the Mughal
commander, unwilling to spend the
monsoon months in his lonely perch,
came down to the plains, while the
hardy Marathas, awaiting the
opportunity, moved in.
(Continue to 2nd post)