Short answers, pulled from the story.
Lord Mornington served as Governor-General of British India during this period of instability. He repeatedly offered subsidiary treaties to both the Peshwa and Scindia but faced strong refusal from Nana Fadnavis.
December 1802 saw the conclusion of the Treaty of Bassein between Peshwa Baji Rao II and the British East India Company. This agreement ceded territory to maintain a subsidiary force while prohibiting the Peshwa from making treaties with any other power.
Scindia rulers of Gwalior and Bhonsale rulers of Nagpur and Berar specifically contested the agreement immediately. Their opposition created fractures that the British exploited to divide and conquer the confederacy.
November brought further defeats when Lake defeated another Scindia force at Laswari. Later that month, Wellesley achieved victory over Bhonsle forces at Argaon on the 29th of November 1803.
He surrendered Hisar, Panipat, Rohtak, Rewari, Gurgaon, Ganges-Jamuna Doab, the Delhi-Agra region, parts of Bundelkhand, Broach, some districts of Gujarat, and the fort of Ahmadnagar. These concessions represented major territorial losses for the Marathas across multiple regions.