Dear Sir,
Hope you are doing well !!
Cost of improvement is the capital expenditure incurred by an assessee for making any addition or improvement in the capital asset. It also includes any expenditure incurred in protecting or curing the title. In other words, cost of improvement includes all those expenditures, which are incurred to increase the value of the capital asset. However, any expenditure which is deductible in computing the income under the heads Income from House Property, Profits and Gains from Business or Profession or Income from Other Sources (Interest on Securities) would not be taken as cost of improvement.
In your case, you can include expenses on the regularization of title, boundary wall, purchase of fire fighting equipment, plants purchase etc.
However, salaries paid to staff would not be treated as cost of improvements.