Ishan Kishan moved to a career-best 273 on day two in Thumba, propelling Jharkand to 493, before Delhi captain Unmukt Chand (89*) and wicketkeeper Rishabh Pant (107*) revived the side from 74 for 3 to 225 for 3 by stumps.
Kishan added 111 to his overnight total, taking charge of the run-scoring while Shahbaz Nadeem and Vikash Singh kept him company. Vikash scored just 2 in the pair's 85-run ninth-wicket stand. Kishan was the last wicket to fall, having scored well over half his side's runs, despite coming in at No. 6.
Delhi then subsided to 74 for 3, before Chand and Pant put on an unbroken 151-run stand by the close of play. Pant was the more aggressive of the two, hitting eight sixes and seven fours, and striking at 127.38. Delhi still required a further 69 to avoid the follow-on.
In a 13-wicket day in Vadodara, Karnataka bowled out Vidarbha for 176 to take a 91-run first-innings lead, before scoring 108 for 3 by stumps.
Resuming at 10 without loss, Vidarbha moved to 151 for 4, but collapsed to lose their last six wickets for 25 runs. The collapse was orchestrated by Shreyas Gopal, who took 3 for 22, and Vinay Kumar, who took two of the remaining lower-order wickets. Jitesh Sharma top-scored with 61. In their second innings, Karnataka lost Mayank Agarwal, Robin Uthappa and Manish Pandey, but opener R Samarth was unbeaten on 45.
Debutant SF Khan scored 110 to help Rajasthan up to 323, before left-arm pacer Aniket Choudhary's 4 for 34 left Odisha languishing at 143 for 8 by the end of the second day in Patiala.
With Rajasthan resuming at 249 for 5, Khan added 45 to his overnight score before falling to Odisha captain Govinda Poddar, whose 3 for 59 were the best bowling figures for his side. In reply to Rajasthan's effort, Odisha slid to 66 for 6, before Deepak Behera's unbeaten 49 restored a measure of respectability to their score.
Right-arm pacer Arup Das took 7 for 39 to leave Saurashtra at 121 for 9 against Assam at Eden Gardens.
After no play was possible on the first day, Das ran through Saurashtra's batting order with seven wickets in the 43 overs of play on day two. The other two wickets were taken by his new-ball partner Krishna Das. Saurashtra had suffered a horrendous start, stumbling to 39 for 6, before lower-order contributions from Jaydev Unadkat (31*), Dharmendrasinh Jadeja (22) and Deepak Punia (16) afforded them some relief.