The 25-year-old Band Baaja Baaraat actress is co-producing the action thriller about a road trip gone wrong with Phantom Films.
Rajkummar, 29, says the decision to back off from the much-delayed project was mutual as he had already committed to another film and he has no issues with Anushka.
"I never signed NH 10 officially. I was supposed to do it. Then it got delayed. Then I moved on to other films like Kai Po Che and Shahid. Then I started working on another film. I can't do two films at the same time. I prefer doing one film at a time," Rajkummar told PTI in an interview on the sidelines of IFFI.
"So it was a mutual decision. I share a very good relation with the team. I think Anushka is also a very sensible girl. She is a really good actor and I don't think she will do anything like that," he added.
According to some reports, Anushka decided to replace Rajkummar with actor Neil Bhoopalam, who is currently a part of Anil Kapoor's 24.
Rajkummar's last three films - Talaash, Kai Po Che and Shahid have been hugely successful. In Shahid, directed by Hansal Mehta, the actor received rave reviews for his sensitive and accurate portrayal of lawyer and human rights activist, Shahid Azmi, who was assassinated in 2010 in Mumbai.
When asked if the success of the film has sunk in yet, Rajkummar said, "Yes it has in a way. We have got a lot of great response. Everyone who has seen the film has loved it. I think it is a great feeling. But now it's all over and I have moved on to another film... I have undertaken a new journey."
Shahid's success has also paved a way for a second collaboration between Rajkummar and Mehta. The duo will work together in City of Lights which is being produced by Fox Star Studios and filmmaker Mahesh Bhatt.
"We have started working on that. City of Lights is an official remake of the 2013 British-Filipino film Metro Manila. We are just adapting it to the Indian context. It's a great script. It's a human drama about a couple," he said.
Rajkummar had a rather unconventional Bollywood debut with Dibakar Bannerjee's anthology film Love, Sex Aur Dhoka in 2010. But the actor has done pretty well for himself in the last three years.
Rajkummar says he does not bother much about the praise that is coming his way and wants to rather focus on building his career on his achievements.
"It feels great. I am really happy and thankful to God that my career is going in a correct direction. It is very flattering. But I feel it's too early to begin to enjoy it. I still have a long way to go. The start is really good. I just want to concentrate and not get carried away by all the laurels that are coming my way.
"I want to be honest to my craft. It gets a little difficult dealing with the fame and adulation. But you always have a choice. You either get carried away or not get affected and continue to do your work," Rajkummar said.
The actor has recently changed his surname from Yadav to Rao and also added an extra 'M' to his name. "I always wanted o change it and anyway Yadav or Rao are the same surname, so it does not matter much. My mother asked me to put an extra 'M' and she asked me to do a whole lot of things. I told her I can't do all of that but only this much. I think she is just being a concerned mom just like how all moms are," he said.