4.     If it involves or implies injury to the person or property of another
An agreement, the consideration of which is the causing of an injury to a person or property of another, is void.[Section-23] Injury means criminal or wrongful harm.

Case-
a)    An agreement by the proprietor of newspaper to indemnify the printers against claims arising from libel printed in the newspaper is void. W.H. Smith & Sons v. Clinton

b)    A bond, which compels the executant to daily attendance and manual labor until a certain sum is repaid in a certain month and penalizes default with overwhelming interest, is unlawful and void. Ram sarup v. Bansi Mudar , (1915) 42 Cal 742

5.     If the court regard  it as immoral
An agreement, the consideration of which is immoral, is void. (Section 23). The scope of the word immoral here extend to the following:

i)     Sexual immorality e.g. illicit cohabitation or concubinage or prostitution.

Case-
a)    A agrees to let her daughter to hire to B for concubinage. The agreement is void, because it is immoral, though the letting may not be punishable under the Indian Penal Code [illustration (k)to section 23]

b)    A gift deed executed in consideration of illicit has been held void, as its object is immoral. Ghumma v. Ram Chandra (1926), 47 All. 619. 

      ii)    Furtherance of sexual immorality.
           
Case-
A man who knowing lets out his house for prostitution cannot recover the rent, it being an act for furtherance of sexual immorality (Choga Lal v. Piyasi)  . The landlord may, however, recover if he did not know the purpose.

      iii)    Interference with marital relation      

Case-
Money advanced to a married woman to enable her to procure and to marry the plaintiff could not be recovered back as the object of the agreement was held immoral(Bai Vijli v. Nansa Nagar). 

iv)    Such acts which are against good public morals.

Case-
a)    An agreement for future marriage, after death of first wife is against good public morals and hence would be void. Wilson v. Cornley (1908), 1 K.B. 729

b)    A, who is B’s mukhtar, promises to exercise his influence, as such with B in favor of C and C promises to pay Rs.1000 to A. The agreement is void because it is immoral.[ illustration (j)to section 23] 

6.    If the court regards it as ‘opposed to public policy
If the court regards the object or consideration of an agreement as opposed to public policy, the agreement is void (Section 23).

The following agreements are considered to be against the public policy.

i)    Trading with an alien enemy:
All trades with public enemies without a license from the government are unlawful. It is now fully established that trading with an alien enemy (i.e. a citizen of the other country at war with the state) is against public policy in so far as it tends to aid the economy of the enemy country. Such agreement is illegal.

ii)   Agreements for stifling criminal prosecution:
It is well-settled law that if a person has committed a crime, he must be punished. Hence any agreement, which seeks to prevent the prosecution of a guilty party is opposed to public policy and is void, for ‘no one can be allowed to make a trade of felony’. Agreement for stifling prosecution cannot be enforced.
    
Example-
Where the offence is non-compoundable as where the charge is one of criminal breach of trust and the offence is compounded by the accused passing a bond to the complaint, the latter cannot recover the amount of the bond.
           
Case-
Where A agreed to execute a kabala of certain lands in favor of B in consideration of B abstaining A with respect to an offence of simple assault which is compoundable, it was held that the contract was not against public policy and could be enforced. Amir Khan v. Amir Jan (1898) 3 C. W. N.  5. 
   
 
iii)        Agreement interfering with the course of justice:
An agreement for the purpose of using improper influence with judges is void.

Example-
An agreement not to disclose misconduct to the other interested party or an agreement to influence a judge to induce him to decide the case in a party’s favor, is obviously opposed to the public policy and is void.

Case-
An agreement to pay a fee to a holy man for prayers for the success of a suit is not an interference with the course of justice. Balasundra Mudaliar v. Mohamed Ossman, (1930) 53 Mad. 29; 57 Mad.L.J. 154. 

    
iv)    Champerty and maintenance:
Maintenance is an agreement made by a disinterested party for litigation. It is a valid agreement. Champerty is an agreement made by a person to help a party to litigation, provided that the party receiving help promises to share the fruits of the litigation in the event of a favorable decision obtained by him in the suit.
 
Case
A contract to assist litigant so as to delay the execution of a decree against him is opposed to public policy and cannot be enforced. Nand Kishor vs Kunz Behari, (1933) All. L. J. 85. 

v)         Traffic in Public Offices:
Agreements for sale or transfer of Public Offices or for appointments for Public Offices in consideration of money are illegal, being opposed to public policy. Such agreements, if enforced, would lead to inefficiency and corruption in public life.

Case-
a)    An agreement to procure Knighthood made to a charity is void. Parkinson v. College of Ambulance Ltd.(1925) 
b)    The priests of a public temple agreed to share the offerings made to the deity. It was held that their arrangement was not against public policy. Kallu v. Rajinder(1922). 
c)    If A pays money to B who promises to use his influence and to secure A’s son and appointment in the public service, A cannot recover the money if his son does secure the appointment. Ledu v. Hira Lal, (1916) 43 Calcutta 115.