(7) It has to borne in mind that the scheme floated by the respondent-DDA is a non-statutory Scheme. The letter of allotment issued by the Dda is an offer which the allottee may or may not accept. If he accepts, then a concluded contract comes into existence and the allottee is bound by the terms contained in the letter of allotment including those relating to payment and delivery of possession. It is an admitted position that in a draw held on 15.12.1989, the flat No. 53, Block-B, Pocket- 11, (2nd floor) was allotted to the petitioner vide allotment-cum-demand letter Annexure-D.By that letter of allotment the petitioner was required to pay a sum of Rs. 1,54,700.00 towards disposal cost of the flat. On 2.2.1990 the petitioner requested for a change from 2nd floor to the ground floor on account of his wife's illness and on getting no immediate response from the respondent in this regard, he deposited the amount as demanded by the DDA. Thus, on such payment made in accordance with the terms of the scheme and the letter of allotment, a concluded contract had come into existence and the DDA was under obligation to hand over possession of the flat No. 53, Block-B, Pocket-11, Sector-18 (2nd floor) to the petitioner. However, it appears that on a consideration of the petitioner's representation dated 2.2.1990, the respondent-DDA took a sympathetic view on humanitarian ground by agreeing to include the petitioner's name in the next draw of lots for allotment of a flat at ground floor. Consequently, in a draw held on 3.7.1990, the petitioner was allotted a flat bearing No. 10, Block-B, Pocket-7, Sector 17, Rohini (Ground floor) vide allotment-cum-demand letter dated 5.2.1991. By that letter of allotment, the petitioner was required to deposit Rs. 2,60,438.67 towards the disposal cost of the flat. Thus, the allotment dated 5.2.1991 was a fresh allotment of flat or fresh offer for all intent and purposes and the petitioner was at liberty either to accept the offer or refuse it. In a transaction for sale of immovable property, among other material terms, the price/premium should be settled to conclude a valid and binding contract between the parties. Where the DDA enters into such a transaction, it is bound to charge premium/price only at the predetermined rates in force on the date of issue of the letter of allotment. If in case the petitioner is not willing to take or accept